A comical way of saying "Problem" (pronounced poor-blum). Derived from the misspelling of the original word, "porblem" is usually used when the issue is blatantly obvious and/or vital to the action or operation.
Pvt. Guy beached the multi-billion dollar U.S Destroyer on a deserted island. This is a porblem.
Guy 1: Did you finish your paper?
Guy 2: Shit, we had a paper due today?
Guy 1: Yeah, and it is worth 55% of your entire grade
Guy 2: Damn, I appear to have a porblem!