PulpMind

Don't give up on the friendship. You have a ton of fun with her, and regardless of anything romantic, having a good, kick ass time with people is more rare than anyone would have anyone else believe. Women (and men!) love communication.
If I were in your shows, I would find a situation in which you can be frank with her... that's hard to do at most workplaces, and if it's not possible at yours, maybe be like "hey you're off at 3, right? can I meet you outside?"... you have to judge what you can ask of her in that regard. anyway... tell her "I think you're really awesome and fun. your friendship is important to me and if you like hanging out with me, then nothing should get in the way of that. we're both adults, right? let's be get some icream sometime."

If she still denies your frienship then the only reasonable thing you can do is assume that she actually really did like you and A) ladder theory, and B) she has a boyfriend and is protecting that relationship (FUCK I WISH MY LAST GIRLFRIEND HAD THAT KIND OF RESPECT). Opting to think that she didn't like you will only poison future attempts at man-woman interaction. True or not, they get in the way of greater truths.
At this point you're like "no way, she's hot and I'm totally not" but you know what? Shut the fuck up. Women are not as shallow as we (men) are. Well, except about cock. That whole "it's how you use it" thing is only about 60% true. But you don't have to worry about that in this situation. In this situation, you met a mid-20's girl (post shallow age) who met a really sweet guy that she really got along with. All she was thinking about was the potential that she could be with a really great, nice guy. Then that guy was not confident and didn't make a move. Fuck, I hate that shit. Why the hell do men always have to make the move? Women's lib my fucking ass. Whatever - the reality is, you didn't make the move, so that made you a friend for an indeffinite period of time. When you did make a move, obviously, it became awkward. Now you must communicate with her, confidently, and tell her how it's going to be, cuz her friendship is awesome, regardless of whatever you said before.

In closing, DO NOT CONFUSE CONFIDENCE WITH A BLOATED EGO. Know your humility and be humble.
-----Added 27/1/2009 at 06 : 27 : 33-----
Also...
Some women (and men) are just fucking stupid.
Because of what is essentially a mental illness, some people hop around from one relationship (friendship and/or romantic) to the next. Indulging to the fullest extent possible, then, after having sucked all the energy out of that relationship, leave it behind and move on.
I think they're commonly called succubus.
Fuck those bitches and assholes.

I hope your friend is just in need of reassurance of your intentions of friendship, and not one of those kinds of cheese maggots.