diff --git a/src/Main/Base/Project/Src/Dom/Implementations/GetClassReturnType.cs b/src/Main/Base/Project/Src/Dom/Implementations/GetClassReturnType.cs
index 57702fc2fc..25f5b41b2e 100644
--- a/src/Main/Base/Project/Src/Dom/Implementations/GetClassReturnType.cs
+++ b/src/Main/Base/Project/Src/Dom/Implementations/GetClassReturnType.cs
@@ -94,7 +94,10 @@ namespace ICSharpCode.SharpDevelop.Dom
 			get {
 				string tmp = base.Namespace;
 				if (tmp == "?") {
-					return fullName.Substring(0, fullName.LastIndexOf('.'));
+					if (fullName.IndexOf('.') > 0)
+						return fullName.Substring(0, fullName.LastIndexOf('.'));
+					else
+						return "";
 				}
 				return tmp;
 			}
diff --git a/src/Main/Base/Project/Src/Services/ParserService/ProjectContentRegistry.cs b/src/Main/Base/Project/Src/Services/ParserService/ProjectContentRegistry.cs
index 697bd777b9..b18cfac6d8 100644
--- a/src/Main/Base/Project/Src/Services/ParserService/ProjectContentRegistry.cs
+++ b/src/Main/Base/Project/Src/Services/ParserService/ProjectContentRegistry.cs
@@ -177,6 +177,10 @@ namespace ICSharpCode.Core
 						contents[pc.AssemblyFullName] = pc;
 					}
 					return pc;
+				} catch (Exception ex) {
+					WorkbenchSingleton.SafeThreadAsyncCall((Action3<string, string, string>)ShowErrorMessage,
+					                                       new object[] { itemFileName, itemInclude, "Error loading assembly:\n" + ex.ToString() });
+					return null;
 				} finally {
 					#if DEBUG
 					LoggingService.DebugFormatted("Loaded {0} in {1}ms", itemInclude, Environment.TickCount - time);