Touch phone as a modem persistent problem!!!

[sgtgallagher0321]

i have had an htc touch going on a good bit now. i am still having this same issue that i posted before, when i set up my internet connection threw i.s. within five minutes i am kicked off and have to connect again if it will even stay connected. i have tried the stock carrier rom and multiple custom roms, nothing seems to help. my computer uses windows vista, does anyone know if it could be a phone as a modem driver issue and if so where to get them. any ideas tips anything at this point would help. i really appreciate everyones help on this forum.