Question about Sony PDA (PEG-SJ22/U)?

Is the Sony PDA Clie (PEG-SJ22/U) compatible with the Sony Memory Stick PRO (512 mb). I try to insert the card into the device and it tells me that there is no memory stick detected. The PDA is refurbished and about 4 years old but it still works great. I try to perform a HotSync operation to download some images onto the device and it tells me that there is no connection established with the computer. What might be the problem?