I have to agree, flirting is just flirting, and when you don't attach anything to flirting it becomes light and fun.
It's a pain in the butt when expectations don't match up with reality and it really hurts especially when there's romance involved.
The only advice I can give you is to take everything at face value. She flirted with you because you're a friend who is very flirtable by the sounds of it, and she liked you. Furthur to that she said that she's not ready to go out with anyone and that guys have messed her around. Take her by her word, she wasn't playing mind games and she wasn't meaning to mess you around either. She was just socially flirting with a friend without any attachments.
Being in a very similar situation about 9 months ago, a friend of mine said to me "I like you, but I'm not ready for a relationship right now.", so I didn't ask her out. It turns out she did want me to ask her out, and that by the time I found that out she wasn't speaking to me.
So in that respect, perhaps your friend does want to go out with you, but doesn't want to take it into a relationship due to past experiences. Perhaps take her on a date instead. A no now doesn't mean a no forever.
