Hi Simon,
I wonder if this would work, even if you had a process chain for the re-trigger. Your problem is not PC failure as I understand. The file is getting partially written. Does your PC fails every time or it is successful but the file is getting partially written?
If it is your PC failure, you can have a ABAP block at the end of the chain. The program would check the file location to see if the file is available. If not, it would trigger the chain again. This way you will not need two different PCs.
Event A
EventA triggered PC -> DTP run -> ABAP block which triggers EventA if no file exists.
Goodluck,
Benedict