I'm not 100% sure on your TJ35 since I've never owned a Clie, but most Palm-based devices hard reset using the following steps: (NOTE: Performing a hard reset will delete ALL information from the PDA and restore it to factory default settings.)
1: Press and hold the power button. (don't release until step 3)
2: Press and release (using a paper clip or ball-point pen) the Reset button on the back of the device.
3: When the PALM OS screen appears, release the power button.
If done properly, you'll get the 'Welcome to Palm OS' start-up screen that will walk you through the steps to configure your "new" PDA.
Proceed through the steps to do the initial set up of your device then press the Reset button on the back of the device again to 'reboot' it. After that you should be able to synchronize the PDA with your PC to restore your files, contacts, databases, programs, etc.
If you still get the same error message after performing a hard reset, you might need to contact Sony support to have the device serviced.