This is with ooRexx 4.1.1 beta (build date: Feb 26 2012), Windows XP SP 3.
Received a short Rexx test program, which uses the ooRexx framework log4ooRexx. Upon termination (the last logged entry in the logfile can be found after the crash in the file) a Windows crash popup window occurs.
To duplicate: please download the attached file and unzip it. Then run "rexx-log-test.rex". At the end of the run the exception occurs.