It sounds like she just isn't ready yet. Potty training cannot be forced, and if the child isn't ready she just won't cooperate. I learned the hard way with my oldest, who at 8 still has accidents from time to time. The other two I had no problems with, because I let them lead me to training. My son was more than 3.5 before he trained; I was beginning to think he'd be in kindergarten in diapers. I didn't push, though, because he was so resistant and I didn't want to clean up poop from all over - diaper changes were easier. One day he just woke up and said "I'm going to use the potty now" and he did. He never had an accident. My now 4 year old wanted to train at about 2.5, but I didn't want to because I was pregnant and figured she'd regress when her brother came. I did make the potty available to her and praised her like crazy when she used it, though, and she basically trained herself. By 3, long after her brother was born, she was done and didn't have accidents either. My suggestion to you is to back off a little bit and let her lead you - when she's ready, she'll let you know. Good luck!
F., mom to 4 under 9
http://F..typepad.com