I had the same issue.
After some trial and error I have found that the problem is that VS does not allow file names to be "ProjectTypeGuids.cs"
Really strange :)
The workaround for this is to simply rename the file:
You will also have to rename the file in the ICSharpCode.SharpDevelop.csproj file.
So you will only need to rename the file (the defined class name can stay the same).