I've actually just exprienced this again this morning, as it has happened to me before....
When the MS error report appears click on details now look for the file name for instance mine was xvid.ax. you then do a search in your HD and locate the file and delete it.....

As far as I can tell the problem file excisted in my dvd santa and when I deleted the bad file it stopped santa from working, so I reloaded santa, so I can finish my burning and haven't opened my shared folder again today(want to finish the burning first)

The 1st time I had 3 files, and they were movies that must of gone wrong and I just deleted them and everything was fine after that.
Its not a virus, so dont worry about that....
I hope this helps you, please let me know how you go.....