Chasing Pavements -- What does that mean?

So I just got the CD by Adele (I know, a year after everyone else) and I absolutely love it. But as a Merican, I have no idea what she’s means in the song Chasing Pavements, when she sings, “Should I give up, or should I just keep chasing pavements, even though they lead nowhere?” I am aware that pavement = sidewalk, but chasing sidewalks doesn’t get me far, meaning-wise.

So naturally I first employed Le Google-fu. This told me, interestingly, that Urban Dictionary listed “chasing pavements” as slang for some raunchy buttsex acts, based on “pavements” being British slang for “ass” (or “arse”). This led in turn to an interview with Adele herself, in which she said that was complete crap, that the term wasn’t even in UD until her song came out, implying that some anonymous internet wanker had just made up the worst possible “definition” of “chasing pavements” and stuck it in UD.

So, British Dopers, or other enlightened Dopers: First, is “pavement” slang for the butt? (And if so, why?) If yes, it’s hard to see how Adele could protest the song doesn’t mean “chasing ass” because that would be the obvious interpretation. Second, if not, is “chasing pavements” some pre-existing slang term for something? If so, what? Third, if it’s not a known slang term, is it still a phrase you would understand or assign some meaning to upon first hearing it? Cause frankly as an American I get only the broadest gist of what, according to her interview, she was trying to say.

I sort of vaguely remembered the story, so I had to consult Ye Olde Wikipedia. Here you go.

I’ve heard it mainly as “chasing pavement” (without the s), and it always meant chasing something that isn’t really there.

The Urban Dictionary counterattack theory sounds good to me.