Glad to help!
Is there a stack trace in the log? @mstormi reported something similar, but I don’t recall how/if it was resolved. Have you restarted OH? Which version of OH are you running? Which version of Jython?
In looking at the trace that Markus provided, I suspect this could be due to an issue with the SD card. Are you using an SD card, is it old, and have you tested it lately?