When you call xsd2code with only the help parameter, it crashes with a "Illegal characters in path" error:
Xsd2Code Version 3.5.0
Code generation utility from XML schema files.
Unhandled Exception: System.ArgumentException: Illegal characters in path.
at System.Security.Permissions.FileIOPermission.HasIllegalCharacters(String str)
I have added a patch that will fix this issue.