The Cold Fusion Application Server service terminated unexpectedly

I am having a problem where the CF Service is unexpectedly terminating. After a code upgrade this week (that allowed me to changed the application from single threaded to multithreaded in CF Administrator), errors began to appear in Window Event viewer that 'The Cold Fusion Application Server service terminated unexpectedly'. This occurred every few minutes until I backed the changes out.

I tested the code in dev with 12-14 users hitting the server for 15-20 minutes and everything worked fine. The baffling part is that there is absolutely no correlation between errors in the CF Logs and the times at which the server stopped, in fact in many cases there were no errors at all for several minutes before the server terminated. Moreover, all the errors that occurred during this period are errors that had been occurring in the logs for the last 6-8 months.

I have found very little help in the forums on this issue, only that it could possibly be a cflock issue. One difference I have found is in how IIS is set up. For RECS the Application Protection is set to 'Medium( Pooled )'. I found a tech note that said CF 4 and later should always be set to 'Low( IIS Process )' but the error it quoted is not one we are getting. I have researched the difference between these two settings but am unclear whether this could cause the problem I am having, especially since Dev worked fine it is set to Pooled also.

Has anyone had this problem or know how to fix it?

What version of CF is this?