I recently noted the same problem with my Handspring which I was using while my Palm had the battery replaced.
I uninstalled the Palm Pilot for Expodev program via the control panel, Windows XP. Then I reinstalled the program on the desk top which, when the Handspring was hot synced, resinstalled the ExpoDev program on the Handspring. Performing a "fresh reinstall" of the ExpoDev program was successful in allowing me to sync some new film files, etc.
I also accessed the Palm Desk Top, and turned off the hot sync of ADDIT which I think is involved with adding programs and information directly from Palm. Be sure to click the button that makes the ADDIT feature never sync unless you change the parameters.
I am not using my device for any thing other than ExpoDev. Thus I have no need for any of the other features in the Palm program.
As far as I know, there is no way to directly remove ExpoDev from the Handspring without going via the desk top on the computer.
See if you are successful, and please let me know.