Welcome to the phantom button club on the fascinate.
Sadly I have found nothing that can permanently fix this issues. I do not recommend swapping for a factory refurbished at this time. This seems to be a software issue and not a hardware issue if you ask me.
What ever button is messing up at the time I try to use usually 1 or 2 times to make it stop thinking it is being pressed.
Use the power button and ask the the phone to power down.
Wait a minute
I like to clean my screen at this time
Use the power button and ask the phone to power up.
Enjoy the phone till the next time it happens.
This problem came with the 2.2 froyo release and was not present under 2.1.
There is another thread here about the camera taking screen shots which is part of the phantom button presses.
Don't forget to call and post on forums about the phantom button presses because Verizon doesn't believe us.
I have been having this problem for the better part of 6 months now. Never seems to be the home button, only the back button. It will keep my phone from turning the screen off, so my battery life suffers. Always hoping for a fix.