This is a limitation of Windows and not a bug of BFBC2 Toolkit.
For now, try to keep the root path short for both BFBC2 and the tool.
I will see if I can find a workaround for it.
If you only need extra length for "initial file meddling" I seem to understand you can just call the unicode function.
Explorer would still limited though, and that's only been lifted in 1607.
This is a limitation of Windows and not a bug of BFBC2 Toolkit. For now, try to keep the root path short for both BFBC2 and the tool. I will see if I can find a workaround for it.