I've had issue with this before - how do I know what the codes mean?

I'm getting a returned value of -1 on trying to Run an exe in SB6.... so
what does it mean?.. and how would I find that information?

Googling for Windows System Error Codes reveals that they *start* from 0.
http://msdn.microsoft.com/en-us/library/ms681381.aspx

So what then does -1 mean?

Steve