The known issues on the PE51EX :
(1) PE51EX driver does not support PowerMacG5.
(2) Mac OS 10.4 driver might hang up when returning from the sleep.
(3) PE51EX does not support surprised removal.
(4) Click [PE51_Driver_Uninstaller] icon, you will see a warning message as follows:
"PE51_Driver_Uninstaller is an application downloaded from the internet.
Are you sure you want to open it?"
To uninstall PE51 driver, click the "Open" button.