1) Is your N900 stock or are you using Titan's power kernel? 2) Did you download the scripts and copy them to the correct folders? 3) Did you make the scripts executable? 4a) Did you modify the enable script in the if_up.d folder? 4b) Did you edit the APN to either epc.tmobile.com or internet2.voicestream.com? 4c) Are the username and password blank?