Creating Hassel at Hasselt with board 92 and 71. Adding overlay X19 causes the uncaught exception. Apparently uploading the log file is not enabled here.
Both your versions of VASL and Vassal are quite out of date. If you’re experiencing the bug I think you are, you won’t have this problem with the current versions.
You can paste the errorLog here, preferably fenced with triple backticks so that it’s formatted as code: