PM hack security problem, Please help?

I installed the PM hack and it seemed to be working great until there were many users on the board at once.
Somehow the PM's get mixed up and users can read each others PM's.
Is anybody else having this problem?
Any ideas how this could happen and how to fix it?

Thanks,
Roy

How strange! I've average about 110 users during peak times and never had a PM mixup reported to me (and believe me, they would tell me)

Like wise with over 260 + users. No problems at all.

Your best bet is to start over and read the instructions from scratch. Follow them very carefully as it is a long modification to install.

Good luck