trace on kills IIS

This concerns IBM Informix Dynamic Server Version 11.70.TC3IE on Windows Server 2008 sp2 . I had some stored procedures that were using a "debug file" to write out a few lines to the sqexpln folder for my own information. These were mainly nightly tasks that were low-use and did not present any performance issues ( IDS 9.4) . They were usually something like LET nrows = DBINFO('sqlca.sqlerrd2'); trace nrows || " rows purged"; But when we went to 11.70, these procs took the IDS down at night when they ran. There was always a file in the ids folder that stated that the service was stopped from the outside (or some such verbiage). I had to use the timestamp to figure out what it was. It took days because I was astounded that IBM would leave a bug like that in a product. I took out the debug file and recompiled all of the procs and the problem went away. Has anyone had any similar experiences?