Lately for one of the user I run into following problem with Purchase approval workflow. During Workflow process assignment customer get error and Workflow is stopped. We get following error:

"User abc has no access to menu item PurchReqTable.” where abc is user to who workflow item should be assign

The root cause of this behavior was of course connected with user permissions. User had too low permission to be able to assign to needed task item. It happens that user was missing permission: Accounts payable -> Miscellaneous
First of all when you assign the permission to Workflow on permission form you should change Viewing from "Security" to "Workflow", then you are able to assign needed permission for selected Workflow. Although when you assign all permission for Accounts payable -> Purchase requisition -> Project purchase requisition approval you still get the same error. I found that menu item PurchReqTable in \ AOT \ Menu items \ Display \ PurchReqTable and I found out that security key assign to this menu item is: VendMisc So in Security view you need to assign user permission Accounts payable -> Miscellaneous