Workflows and "The data source control failed to execute the insert command. "

I recently took over the design of a site that makes heavy use of Designer created workflows and custom Edit Forms.

While trying to figure out how the system worked, I ran into this error when starting a workflow:
"The data source control failed to execute the insert command. "

After googling around for a few minutes, I found this:

http://purbayubudi.wordpress.com/2008/09/06/moss2007-the-data-source-control-failed-to-execute-the-insert-command/

I had never actually seen the remove workflow page on a list before. Interesting. I was able to remove the workflow from the list. Once I re-opened the workflow and saved it, the workflow starting working again. Weird. But at least it works again.