The locking model of DOORS means that the creation of links from RQM (Rational Quality Manager) to DOORS will fail if the module or object is locked in DOORS with the following error:
If you "Cancel", nothing should happen. No link is created in either application. If it's you who has the module open in exclusive edit mode in DOORS (and I do this all the time, I guess I'm not alone...), it's an easy fix. Close it in DOORS and check "Try again".
But if you continue and "Save the partial changes", what have you done? You have created a link from RQM to DOORS but not from DOORS to RQM. This could impact reporting if the reports are only looking in DOORS as there is no link to the test case in DOORS. How do you fix that?
In DOORS, you could create the link to the RQM object. But also in RQM there is a little known but very nice feature that came in 4.0.1 for checking the state of these links. See: Ability to see back link status in traceability view. Here's a screenshot from RQM 5.0.2 RC1:
The missing links are identified and can be fixed by the broken link icon.
This has been implemented as a user setting. A customer recently asked why is this not the default? Well, consider the actual impact of this if you have thousands of test cases linked to requirements. It will send thousands of requests to DWA. With hundreds of users, DWA would need to be scaled to manage that increase in load. I would leave this feature for the users who need it. I would not activate it for every user as every user is not interested in the link status.