Garmin 610 importing more than "new" workout only (Read 219 times)

Ever since changing from a Garmin 305 to a 610 (last August) when I upload workouts it always not only includes the "new" workout, but also the one prior, which already has been uploaded.  Each time I have to delete the old workout.  This happens even though I have the "new workouts only" tab checked. 

This is a minor inconvenience, but I was just wondering if this is common, and/or is there something I can do to correct it? 

Running Windows XP SP3, IE 8 and IE 7 (work and home computers).

Thanks Burnt Toast, I figured this was out there somewhere.