I installed Adobe Reader 7 on my desktop and activated it. I also installed Adobe for the Palm on my Palm and activated. No problem. I then purchased a pocket pc. Hooked that up and loaded Adobe for the pocket pc on it and tried to activate but it will not activate. The error I get is "User's signature is invalid". After several attempts I uninstalled Adobe off of the desktop and pocket pc ( I no longer need the Palm). I reinstalled and tried to activate the desktop and it would not activate with the same error message. The .net passport still shows both the desktop and palm as being activated, however its not and when I go to read a digital edition it takes me to the activation screen. I am now at a total loss as to how to fix this. If anyone knows how, please let me know.