It could be a bug. Try it with 5.8.0, which has been released some weeks ago. And yes, I know you don't want to upgrade the production server, but you do have a test and a development area, don't you?

If you don't have a memory leak on 5.8.0, the bug was fixed. If it's still there, please use the "perlbug" command to report a bug.

Abigail