Viewsonic V36 Constant Recalibration

I like my V36 except for the fact that I frequently must align the
screen before i can get anything constructive done. For example, I
might tap the stylus on the backspace and the "o" is inserted or I
can't click OK or something. I thought I had fixed the problem by
making the keyboard larger, but that seemed to be a temporary fix b/c
it starting to happen again. It's not unusual for me to have to
recalibrate the thing 2 or more times in a row. Has anyone else had
this problem? Is it fixable? Am I gonna have to exchange it for a new
one?