This error occours when starting the nsclient program for Nagios. Windows 2003 server sp1’s new Data Execution Protection (DEP) (stack protection) causes this. Which means the process was aborted and windows says “The process terminated unexpectedly”.
To fix it:
To make an exception for certain programs to run without DEP you need to do the following in W2k3 SP1: Right click “My Computer” then “Properties”. Click the “Advanced” tab then click the “Settings” button under the “Performance” section.
Click on the “Data Execution Prevention” tab and then click the radio button “Turn on DEP for all programs and services except those I select”.
Then click the “Add” button and add your exe you don’t want stack protection for.