diff --git a/src/main/java/org/olat/core/commons/fullWebApp/BaseFullWebappController.java b/src/main/java/org/olat/core/commons/fullWebApp/BaseFullWebappController.java
index f5431a16c098f6d85cbfcc95829ab94db023b577..af90cd37ce2f0a51c064e43592419286a89227bf 100644
--- a/src/main/java/org/olat/core/commons/fullWebApp/BaseFullWebappController.java
+++ b/src/main/java/org/olat/core/commons/fullWebApp/BaseFullWebappController.java
@@ -1352,15 +1352,17 @@ public class BaseFullWebappController extends BasicController implements DTabs,
 			userToolsMenuCtrl.lock();
 		}
 		
-		for(int i=dtabsControllers.size(); i-->0; ) {
-			DTab tab = dtabs.get(i);
-			if(lockResource == null
-					|| !lockResource.getResourceableId().equals(tab.getOLATResourceable().getResourceableId())) {
-				removeDTab(null, tab);
-			} else if (lockResource != null
-					&& lockResource.getResourceableId().equals(tab.getOLATResourceable().getResourceableId())
-					&& lockStatus != LockStatus.locked) {
-				removeDTab(null, tab);
+		if(dtabsControllers != null) {
+			for(int i=dtabsControllers.size(); i-->0; ) {
+				DTab tab = dtabs.get(i);
+				if(lockResource == null
+						|| !lockResource.getResourceableId().equals(tab.getOLATResourceable().getResourceableId())) {
+					removeDTab(null, tab);
+				} else if (lockResource != null
+						&& lockResource.getResourceableId().equals(tab.getOLATResourceable().getResourceableId())
+						&& lockStatus != LockStatus.locked) {
+					removeDTab(null, tab);
+				}
 			}
 		}
 		navSitesVc.contextPut("visible", Boolean.FALSE);
diff --git a/src/main/java/org/olat/course/nodes/GTACourseNode.java b/src/main/java/org/olat/course/nodes/GTACourseNode.java
index c48259b614611c6e96caaf5cdf95a7838351c0e1..c0121237445a4b0479d393f375b5181558327984 100644
--- a/src/main/java/org/olat/course/nodes/GTACourseNode.java
+++ b/src/main/java/org/olat/course/nodes/GTACourseNode.java
@@ -569,7 +569,7 @@ public class GTACourseNode extends AbstractAccessableCourseNode implements Asses
 				+ "_" + assessedIdentity.getKey();
 		
 		Task task = gtaManager.getTask(assessedIdentity, taskList);
-		if(task != null && config.getBooleanSafe(GTASK_ASSIGNMENT)) {
+		if(task != null && task.getTaskName() != null && config.getBooleanSafe(GTASK_ASSIGNMENT)) {
 			File taskDirectory = gtaManager.getTasksDirectory(course.getCourseEnvironment(), this);
 			File taskFile = new File(taskDirectory, task.getTaskName());
 			if(taskFile.exists()) {
@@ -614,7 +614,7 @@ public class GTACourseNode extends AbstractAccessableCourseNode implements Asses
 				+ "_" + businessGroup.getKey();
 		
 		Task task = gtaManager.getTask(businessGroup, taskList);
-		if(task != null && config.getBooleanSafe(GTASK_ASSIGNMENT)) {
+		if(task != null && task.getTaskName() != null && config.getBooleanSafe(GTASK_ASSIGNMENT)) {
 			File taskDirectory = gtaManager.getTasksDirectory(course.getCourseEnvironment(), this);
 			File taskFile = new File(taskDirectory, task.getTaskName());
 			if(taskFile.exists()) {
diff --git a/src/main/java/org/olat/course/nodes/cl/ui/CheckListRunController.java b/src/main/java/org/olat/course/nodes/cl/ui/CheckListRunController.java
index 6f7878498e4a89cb6b7aca24f7a5aa56dd93ece9..fc6d9850aa82a1a5bd756eb4ed8121a9efdd3796 100644
--- a/src/main/java/org/olat/course/nodes/cl/ui/CheckListRunController.java
+++ b/src/main/java/org/olat/course/nodes/cl/ui/CheckListRunController.java
@@ -348,6 +348,10 @@ public class CheckListRunController extends FormBasicController implements Contr
 			return checkboxEl.getName();
 		}
 		
+		public boolean hasDownload() {
+			return StringHelper.containsNonWhitespace(checkbox.getFilename()) && downloadLink != null;
+		}
+		
 		public String getDownloadName() {
 			return downloadLink.getComponent().getComponentName();
 		}
diff --git a/src/main/java/org/olat/course/nodes/cl/ui/CheckboxAssessmentController.java b/src/main/java/org/olat/course/nodes/cl/ui/CheckboxAssessmentController.java
index fdd24d53217d9f2a744ac0d2ce9a72ee1129baa2..5fae53ee772cedc6f6a288592cae4ca9ff84d8d9 100644
--- a/src/main/java/org/olat/course/nodes/cl/ui/CheckboxAssessmentController.java
+++ b/src/main/java/org/olat/course/nodes/cl/ui/CheckboxAssessmentController.java
@@ -203,7 +203,7 @@ public class CheckboxAssessmentController extends FormBasicController {
 			TextElement pointEl = uifactory.addTextElement(name + "point", null, 5, pointVal, formLayout);
 			pointEl.setDisplaySize(5);
 			
-			MultipleSelectionElement checkEl = uifactory.addCheckboxesHorizontal(name + "check", formLayout, onKeys, onValues);
+			MultipleSelectionElement checkEl = uifactory.addCheckboxesHorizontal(name + "check", null, formLayout, onKeys, onValues);
 			checkEl.setDomReplacementWrapperRequired(false);
 			checkEl.addActionListener(FormEvent.ONCHANGE);
 			checkEl.setUserObject(row);
diff --git a/src/main/java/org/olat/course/nodes/cl/ui/_content/run.html b/src/main/java/org/olat/course/nodes/cl/ui/_content/run.html
index 80f560223af327c7507403cd0d443932d8531cfe..a9f5cb760d3dfeea8820fc9a5f81829a58eedda6 100644
--- a/src/main/java/org/olat/course/nodes/cl/ui/_content/run.html
+++ b/src/main/java/org/olat/course/nodes/cl/ui/_content/run.html
@@ -153,7 +153,7 @@
 				#if($checkbox.description)
 					<div class="o_cl_desc">$r.xssScan($checkbox.description)</div>
 				#end
-				#if($checkbox.checkbox.filename)
+				#if(${checkbox.hasDownload()})
 					<div class="o_cl_file">$r.render($checkbox.downloadName)</div>
 				#end
 			</div>
diff --git a/src/main/java/org/olat/course/nodes/ta/DropboxForm.java b/src/main/java/org/olat/course/nodes/ta/DropboxForm.java
index fde66bcbb942b8b673db99218724b02179304cc7..2a2cccd5dda89993d5686a3c8473e25727526843 100644
--- a/src/main/java/org/olat/course/nodes/ta/DropboxForm.java
+++ b/src/main/java/org/olat/course/nodes/ta/DropboxForm.java
@@ -77,7 +77,8 @@ public class DropboxForm extends FormBasicController {
 	protected void formOK(UserRequest ureq) {
 		fireEvent (ureq, Event.DONE_EVENT);
 	}
-	
+
+	@Override
 	protected void formInnerEvent (UserRequest ureq, FormItem source, FormEvent event) {
 		if (source == enablemail) {
 			confirmation.setMandatory (enablemail.isSelected(0));
@@ -112,7 +113,9 @@ public class DropboxForm extends FormBasicController {
 		confirmation = uifactory.addTextAreaElement("confirmation", "form.dropbox.confirmation", 2500, 4, 40, true, sConfirmation != null ? sConfirmation : "", formLayout);
 		
 		Boolean enableMail = (Boolean)config.get(TACourseNode.CONF_DROPBOX_ENABLEMAIL);
-		confirmation.setMandatory(enableMail);
+		if(enableMail != null) {
+			confirmation.setMandatory(enableMail.booleanValue());
+		}
 		enablemail = uifactory.addCheckboxesHorizontal("enablemail", "form.dropbox.enablemail", formLayout, new String[]{"xx"}, new String[]{null});
 		enablemail.select("xx", enableMail != null ? enableMail.booleanValue() : true);
 		enablemail.addActionListener(FormEvent.ONCLICK);
diff --git a/src/main/java/org/olat/user/propertyhandlers/_i18n/LocalStrings_de.properties b/src/main/java/org/olat/user/propertyhandlers/_i18n/LocalStrings_de.properties
index 324c50aa61a1fbdc6efbfec9cfc345b5a697e48a..d11499e49324ea699b3a0a8e1545116ced549f4e 100644
--- a/src/main/java/org/olat/user/propertyhandlers/_i18n/LocalStrings_de.properties
+++ b/src/main/java/org/olat/user/propertyhandlers/_i18n/LocalStrings_de.properties
@@ -259,13 +259,13 @@ form.group.address=Adresse
 form.group.contact=Kontaktdaten
 form.group.institute=Institution
 form.group.person=Person
-form.group.about=Über mich
+form.group.about=\u00DCber mich
 form.group.officeaddress=Gesch\u00E4ftsadresse
 form.name.birthDay=Geburtsdatum
 form.name.birthDay.error=Bitte geben Sie ein g\u00FCltiges Datum an.
 form.name.birthDay.error.empty=Das Feld "Geburtsdatum" darf nicht leer sein.
-form.name.date.future.error=Das gewählte Datum muss in der Zukunft liegen
-form.name.date.past.error=Das gewählte Datum muss in der Vergangenheit liegen
+form.name.date.future.error=Das gew\u00E4hlte Datum muss in der Zukunft liegen
+form.name.date.past.error=Das gew\u00E4hlte Datum muss in der Vergangenheit liegen
 form.name.city=Stadt
 form.name.city.error.empty=Das Feld "Stadt" darf nicht leer sein.
 form.name.country=Land
@@ -427,5 +427,5 @@ text.element.error.notlongerthan=Wert enth\u00E4lt mehr wie {0} Zeichen
 username=Benutzername
 yph.from=Von
 yph.to=Bis
-yph.err=Bitte geben Sie einen gültigen Wert ein
-yph.infomsg=Bitte geben Sie 'von' und 'bis' Jahreszahlen (JJJJ) ein. <br />Sie können auch '+N' oder '-N' verwenden...
\ No newline at end of file
+yph.err=Bitte geben Sie einen g\u00FCltigen Wert ein
+yph.infomsg=Bitte geben Sie 'von' und 'bis' Jahreszahlen (JJJJ) ein. <br />Sie k\u00F6nnen auch '+N' oder '-N' verwenden...
\ No newline at end of file