HTTPS web pages don't open on Alltel EVDO

[solarliving]

I'm currently evaluating the Alltel PPC6800 or Sprint Mogul service side by side and I can't load Yahoo mail or Sprint my acct page on my Mac ibook os x 10.4.1 with wmwifirouter on firefox or either phone on mobile internet explorer. the connection just seems to time out on certain web pages. I live in a very rural area in Northern New Mexico and I'm on Alltel EVDO when I am at home. I get about a 500K DL connection on average with 2 bars signal strength. any ideas on what to check?
Alltel PPC 6800 rom 2.14.671.3 radio 1.4 prl 40029 sid 1499 (Alltel Santa FE) rx power -104db to -85db
Sprint Mogul rom 2.17.651 radio 1.47.01 prl 60611 sid 1499 (Alltel Santa FE) rx power -104db to -85db

sid 1499 will be my primary data service at home. will sprint SERO cancel my service for continually evdo data roaming on Alltel at around 5gigs data a month?