While I would put nothing past the RATS when it comes to vote fraud, this really sounds like a result of sloppy set up and testing of the machines. Touch panels (think your Palm Pilot) normally have to be calibrated when booted for the first time so they "know" where the user's finger (or in the case of a PDA the stylus) is making contact with the screen. The point of touch is then made to line up with the application display you see on the screen. If the software doesn't know where the center of the screen is it may very well insert a "drift" between where you touch and what part of the application (vote checkbox in this case) records the input.
Could be deliberate but I lean towards bad set up, likely by people that have no idea what they're doing with the technology. If the workers are able to "address the problem as it occurs" this would lead me to believe they're actually resetting the screen calibration. Just a guess.
>>Could be deliberate but I lean towards bad set up, likely by people that have no idea what they're doing with the technology. <<
Oh well. So long as they put the entire nation into Constitutional turmoil, what the hell?