I had an issue with blat yesterday with a new script I was working on. Every time I sent an email, it would crash and I would get “A Win32 command line eMail tool has stopped working.” As this was also running on a Windows2008 server this was also affecting the reliability index on the server – one of the things we check as part of our checkups.
I spent a good while trying to work out what was wrong, typed out the command to send mail and it worked – so I knew the issue was not blat itself. After calling over a colleague to help, demonstrating the (reproducible) problem of pasting the script line and crashing blat I asked what was wrong. The two of us still took a couple of minutes before he realised I had mistyped the server name used to send the mail. Instead of domain.com.s6a1.psmtp.com I had entered domain.com.s6a1.pmstp.com
Sure enough – if the mail server hostname can not be resolved by blat – it will crash. I was also able to reproduce this on my Windows7 machine at home too.

A simple fix but difficult to find after looking at code for a long time – getting someone else to look at your code often does wonders.