Here's an interesting tech support question that came up while i was getting ready for my rehearsal with Midori yesterday - a friend of mine was inspired to get his own Tablet PC (a Toshiba model, i believe) via eBay and a page turning pedal from PedalPax to put together a digital music reading/annotating system similar to what i have. Upon receiving the used Tablet PC, installing PDF Annotator and waiting for his PedalPax pedal to arrive, he was finding that pressing the hardware button for page turns was advancing 2 or 3 pages at a time. At first i thought it might've been a damaged button on the unit and advised him to disable the page turning function associated with it. After receiving the pedal, however, the multiple page turns continued to be a problem. He was so exasperated that he gave me a call without realizing that i was about to start rehearsing in a few minutes.
At first i was pretty perplexed. A hardware button malfunction might've been one thing, but to have a USB pedal coming up with the same bug? Highly unlikely. Then the answer came to me in a flash - you can adjust the keyboard key delay and repeat speed within Windows (to get to the Keyboard settings, in the Windows XP Tablet PC edition press 'Start' on the Start Menu Bar, select 'Control Panel' - make sure you have the Classic View option set - then click on the 'Keyboard' icon). My friend must've had his delay setting much too early and his repeat rate much too fast. By setting both options towards their opposing values, that would solve the mystery multiple page advances by hardware button or pedal device, since both basically function as alternate keyboard entry devices.
i just called my friend and got confirmation that this solution seems to be working so far (hopefully it won't revert to sudden multiple page turns during the middle of a concert!). Oh, and by the way - he reports that the PedalPax pedal unit tends to be very squeaky underfoot, probably because of the type of material comprising the buttons.