We have just implemented revision control on our manufacturing drawings via the Item Master. We have the issue that if the assign item dialog is left open for more than about 5mins, you will revieve multiple errors and won't be able to assign the item. Once the errors occour, you can't assign an item to that assembly.
The most common workflow that results in the error:
1- assign item to top level assembly
2- check that items are being assigned correctly, no missing parameters etc. (if you are playing along, wait with the first page of the assign item wizard open for 5-10 minutes)
3- attempt to cancel out of the wizard because you notice issues with the items being assigned
4- error 1387 - restrictions have occoured. more information available in the Soap Exception detail
5- must click 'next' in the wizard, then try cancel from that page in order to successfully exit.
attempts to assign an item again result in 'error 155 - illegal null parameter passed to server'.
once this happens you have to wait until the next day to try again.
This is consistant across multiple machines and assemblies.