diff --git a/src/Main/Base/Project/Src/Project/Items/TypeLibrary.cs b/src/Main/Base/Project/Src/Project/Items/TypeLibrary.cs
index 88b9e44453..3e7b6d209f 100644
--- a/src/Main/Base/Project/Src/Project/Items/TypeLibrary.cs
+++ b/src/Main/Base/Project/Src/Project/Items/TypeLibrary.cs
@@ -66,7 +66,7 @@ namespace ICSharpCode.SharpDevelop.Project
 				}
 				string[] ver = version.Split('.');
 				
-				return ver.Length == 0 ? -1 : Int32.Parse(ver[0]);
+				return ver.Length == 0 ? -1 : GetVersion(ver[0]);
 			}
 		}
 		
@@ -77,7 +77,7 @@ namespace ICSharpCode.SharpDevelop.Project
 				}
 				string[] ver = version.Split('.');
 				
-				return ver.Length < 2 ? -1 : Int32.Parse(ver[1]);
+				return ver.Length < 2 ? -1 : GetVersion(ver[1]);
 			}
 		}
 		
@@ -146,5 +146,14 @@ namespace ICSharpCode.SharpDevelop.Project
 			}
 			return null;
 		}
+		
+		static int GetVersion(string s)
+		{
+			int version;
+			if (Int32.TryParse(s, out version)) {
+				return version;
+			}
+			return -1;
+		}
 	}
 }