Maybe your mailserver has some limit on sending to prevent excessive bulkmailling? Maybe slow down your script or ask the sysadmin if you are allowed unlimited mail sending? Maybe their counting algorithm isn't exact and each time you run it, a different number of mails get through before they detect you.
I'm not really a human, but I play one on earth.
flash japh
Comment on Re: MIME Lite Module constantly crashing
I added a test to slow down the script (pausing every 200 messages). I have also increased the timeout to 300 seconds (5 minutes.)I'll see what happens.