I reinstall CS3 design premium. Everything seems to be working fine except for Acrobat Pro 8, which won't activate. When you go to Help ---> Activate from the DVD, but it made no difference. When i run acrobot, "Continue Trial or Buy" menu shown, then i enter Adobe CS3 DVD serial number "Invalid Serial Number" shown. now i run trial version, only 19 days remaining, Pls help.... How can I fix this?