Pocket PC Problems

I recently received a used Toshiba e750 Pocket PC. The USB connection between the PDA cradle and my computer has been behaving strangely. I put the PocketMac software (which allows a Mac to "talk" to a Pocket PC) on my computer. It recognizes that the PDA is there, but whenever I try to send a file from one to the other, the computer freezes up almost immediately. I have managed to send a very small (less than about ten KB) text file from the PDA to the computer, but I should be able to transfer larger files. I talked to PocketMac tech support, and they told me to upgrade to OS 10.4.11, reinstall PocketMac, and try again. I did exactly what they said, and it still behaved exactly the same. Has anyone heard of anything like this happening?