My PMH installation will not burn DVDs.

My PMH installation will not burn DVDs. I select "Create Discs" and go through the create process, put a blank DVD in the drive and close the drive. I can hear the drive searching for a few seconds, then nothing. No message of any kind and no further drive activity. I can burn discs, both CD and DVD, with other software, so the drive is not faulty. I was using PMH 5.1, but when i tried to remove and re-install (in case there was some corruption) I couldn't, because I am using XP. I sourced a copy of PMH v2 which installed fine, but I have the same problem when trying to create DVDs - the process stops at the same point and with the same symptoms.
I am now accumulating a backlog of material which I need to get onto DVD and cannot because of this problem.