Auto-Report generation using pdf


My company is using pdf 0.9.7 to auto-generate and save multiple nortel call center pdf reports. We schedule it to run everyday  and the reports save to the designated network drive and it works but the problem is there is no consistency. Sometimes it does not generate at all, so I reboot the server and then run pdf creator. When I try to run some test reports it doesnt generate at that time, and/or generates at some later point of time. could anyone help why does it behave inconsistently. Thanks