in order to debug an installer custom action, simply put the following line where you want the breakpoint to be
System.Diganostics.Debugger.Break();
Note that during installation, the process is running under the msiexec process from windows\system32 and thus any path to files are based on windows\system32 and not program files\your app path
Technorati Tags: Tips hint install
Emad's Blog 
Leave a Reply