To translate an GUID into the RAW value that LDSD uses for Oracle, you can use this handy site to do the conversion
However if I were you, Id report this issue to support as it sounds a bit nasty
Did you ever manage to get a solution to this problem?
We've started having the same problem.
I can find the reminders, and then delete the Reminder by its GUID to temporarily fix the problem, but it just delays it until the next email error occurs.