List Locks doesn't work in branch/workarea

System

I'd like to know if anyone else is having a problem similar to the one we are having. We have a four workareas in a branch in which there are locked files. When we choose "List Locks" from the menu it doesn't return any results. If I run iwlistlocks.exe from the command line on these workareas or the branch they return nothing. The files are indeed locked and you can see some of them by choosing "List Modified" from the menu.

Does anyone have any suggestions on what we can do to fix this? We're running TS 5.01 SP1 (and planning an upgrade to TS 5.52 by end of year).

Sebouh