diff --git a/src/main/java/org/olat/modules/vitero/ViteroModule.java b/src/main/java/org/olat/modules/vitero/ViteroModule.java
index 6c41dd3b867c8cde3b404c101e901b5b574e1dea..5762fa8e23e31dc09a9e9b87867377d70a98a9ac 100644
--- a/src/main/java/org/olat/modules/vitero/ViteroModule.java
+++ b/src/main/java/org/olat/modules/vitero/ViteroModule.java
@@ -231,7 +231,7 @@ public class ViteroModule extends AbstractOLATModule implements ConfigOnOff {
 	}
 
 	public void setProtocol(String protocol) {
-		setStringProperty(PROTOCOL, protocol, true);
+		setStringProperty(PROTOCOL, protocol == null ? "" : protocol, true);
 	}
 
 	public int getPort() {
@@ -247,7 +247,7 @@ public class ViteroModule extends AbstractOLATModule implements ConfigOnOff {
 	}
 
 	public void setBaseUrl(String baseUrl) {
-		setStringProperty(BASE_URL, baseUrl, true);
+		setStringProperty(BASE_URL, baseUrl == null ? "" : baseUrl, true);
 	}
 	
 	public String getContextPath() {
@@ -255,7 +255,7 @@ public class ViteroModule extends AbstractOLATModule implements ConfigOnOff {
 	}
 
 	public void setContextPath(String contextPath) {
-		setStringProperty(CONTEXT_PATH, contextPath, true);
+		setStringProperty(CONTEXT_PATH, contextPath == null ? "" : contextPath, true);
 	}
 
 	public String getDisplayName() {