Slide to answer problem iPhone 3G

I seem to have trouble answering my phone quite frequently because the slide to answer function just does not seem to be responding properly. Ive read around that other people have issues with slide to answer/unlock where the problem is that it is not responding.
My problem seems a bit different because when I get a call, rather than slide to answer not responding at all, I get to slide the bar a quarter or halfway through then it does not detect my finger and the bar slides back to the left. Sometimes I have to try many times before it finally reaches the end to answer, and most of the time I dont even get to answer the call. Immediately after that though, when I get the unlock screen showing my missed call, slide to unlock works just fine so I do not think it is the screen problem.
Occasionally I get to slide the answer bar all the way to the end, but instead of answering the call, the bar just slides back to the left. I even tried sliding the bar to the end and holding it hoping it would answer but as soon as I let go, the bar slides all the way back again.
Has anyone encountered a problem similar to the one I am facing? Anyone got some suggestions on how I can fix this?
MacBook Pro Mac OS X (10.6.2)