Well I'm stumped.... Just spent a day trying to work around this issue, and no luck.....
Pretty simple setup,
3ish year old core2duo dell pc running
Windows 7 x64 running xbmc frodo
Panasonic 42" plasma
Inititially I tried using my harmony 650 remote, tried both recommended tv profiles, and the flirc xbmc profile, programming the flirc on both 0.9.7 firmware and 1.1 beta, also played around with harmony input delay settings as per some other forum posts. No luck on any combination, always ended up with multiple keypresses, usually one of the direction keys, making navigation impossible.
Next step was to ditch the harmony as others are reporting multiple issues, and just try the actual tv (panasonic) remote. Loaded it up and programmed it with both 0.9.7 and 1.1 beta, noise cancellation on and off for both programming and control, tried full keyboard and simple, all the same result, multiple keypresses, and no ability to navigate. Tried programming in situ, and on laptop in dark room, no difference.
I had originally ordered 3 flircs, so tried another in the originals place, changing usb ports and still no joy.... Seems like the multiple keypresses are inevitable with every combination I can possibly try. Hope a solution presents itself, was hoping to use these to simplify my 3 htpcs controls....