I seem to have quite a problem here and am not sure how to get it done...Go to that directory and look at the log file. I used to get that message because the files in the mod had a path name + file name that was too long, but your log should tell you.
Every time i set a mod up and build it, i get the
"modbuilder.exe Error: 0 : Error building JerichosEscalation.mod: C:\Program Files (x86)\Steam\steamapps\common\Company of Heroes 2 Tools\AttributeEditorXML.exe failed with exit code -1."
As i can't get anything done and tried 4 times so far, i just hope someone here can help me with it
Also, a couple of people have reported fixing strange errors by applyihg a big backlog of Windows updates.