I solved my own issue. The table needed to have a key pair. When I first set it up, only RequestId was a key. Now, the RequestId and TaskId form a key pair. I manually added the change to the table as well as the OpenAccess app.config. However, it seems I had to use the tool to regenerate the class for it to work...
Anyway, the error was being thrown because I was trying to insert a record with a duplicate key (RequestId never changes for this loop, only the taskId). I never saw the duplicate key message, however, so it took me a while to realize my mistake.