I had the exact same problem. it seems like it only happens when you use the new 2.1 Android keyboard. I got fed up with it and now I'm using the HTC keyboard. search for it and there's a tutorial on how to install it. I even got the customizable one, where you can choose you own colors and background. honestly, this HTC keyboard works so much better than the default Android one that's offered with the update. hope this helps.
Don't think you can fix the default keyboard...think it's a glitch with 2.1