There is actually no solution for this, just prey and hope ... see here:
Bug 32613 – OSX 10.5: Directory services cache corruption
If you look at what Quanah wrote at the end of my bug report
"There will not ever be a supported OSX 10.5 build of ZCS"
indeed we are planning to migrate our ZCS install to Ubuntu 10.04 LTS when ZCS 6 will be out of its beta stage for that platform.