returns error "wtf?"

Once upon a time, when education was supposedly better than it is today, elementary school grammarians would teach sentence parsing, which involved breaking down sentences to identify what part of speech each word represented. (Presumably, they'd also teach the imprudence of run-on sentences. (And nested parentheses.))

In the world of CGI, a .pl extension generally denotes an application written in the programming language perl. If the application errors out, it may return an error message constructed similarly to this expression. This expression, as used on channel, typically takes the IRC nick (or some modification therof) of the user as a prefix, e.g. returns error "wtf?". It is used in response to someone saying something unintelligible or fragmentary:

The error message wtf? stands for "what the fuck?" and it indicates you have no idea what the person is talking about. What they are saying may not even make sense -- random word strings, unintelligible line noise characters, etc. Thus, returns error "wtf?" is distinguished from context.dll missing or not found and seguementation fault.