I have seen this question on the forums, but no one has seemed to come up with a solution. Upon submission of an infopath form, a workflow is kicked off to edit the document, but the workflow gives the "document checked out" error. I've seen that there is a fix for this that puts a delay in before the actions in the workflow run, but one of the things that the workflow does is set item-level permissions to make sure that only certain people have access. We can't put in a delay for 10 minutes because if the permissions don't get set immediately, an unauthorized person could gain access to the form. Let me know if you have any questions. Thanks.