This is something really annoying about simple error codes. Sure they're lightweight but how the hell am I supposed to know the problem with my input when all the error information I get is "The parameter is incorrect"? I've actually had cases where I disassembled Windows system libraries to track down the exact validation that was failing.
From a user's POV, "I already know what file not found means. You don't have to explain it to me again in your own words."