I have nagios 3.0.1 running on ubuntu 7.10 server and I’m using nsclient++ 2.7 clients. We are about to change our email from lotus notes to ms exchange 2007. Exchange requires the 64 bit version of windows. I can install nsclient++ but when you try to start the service I get a ‘path not found’ alert. Does anyone know of a good 64 bit client for windows? 
Guess I will answer my own question. I’ve always dropped the NSClient++ folder in the C\Windows\System32 folder and installed it from there. That works OK on Windows 2000 and Windows 2003 32 bit. Anyway, I found that if I place the NSClient++ folder in C:\Program Files (x86) where it belongs (duh), it works just fine. Guess you just have to be somewhat smarter than a box of rocks! !lol
thx for the answer to your own question; it might help others (including me :))