Palm Centro 690 (CDMA)

Hello, im really hoping you can help me out. I have the centro and have been trying to get phone as modem to work with no success. I thought it was my laptop and tried others, still doesnt work. I keep gettin error 678. Is there anything i should be doing on the phone? the manual says to just plug it in nd hit go on the sprint program on the laptop. Tech support sucks.. spent 2 hours with them then they gave me the classic "we r gona provision your phone, wait 4 hours" and hung up. Please help!!!