Pdf creator locks up

I am running PDFCreator 1.2.0 on two Citrix servers and experiencing infrequent lockups with PDFCreator. It is running as a service via Firedaemon running under an administrator user account.

What happens is that randomly the queue halts and all futher print jobs are placed on hold until an administrator logs onto the Citrix server and manually starts the PDFCreator program and views the queue. Then the print jobs automatically start printing again once this is done.

Has anyone seen this before or been able to resolve it? I have checked the Windows event viewer for errors but get nothing from PDFCreator to begin troubleshooting it futher.