When validating or saving a Scripting Node with either C#/VB.NET, I'm getting the error message 'Illegal character in path,' at line 0. I am unable to save any changes made to the Process Map.
This also happens on a new Scripting Node (either C#/VB.NET).
In one of the cases, there was a mis-configured .NET Assemblies in Integration.
Verify ALL Assemblies on Local and Store are correctly configured.
Remove any offending assemblies that are not referenced correctly.
You should then be able to validate and/or save your Business Process afterwards.