Although I have the N800 model, I was having the same "loading" problem with RoadRunner webmail here in NC. Today, I updated to the new OS version for the N800 and coincidently, RR updated today to a new version of webmail. When I tried RR webmail today, it works perfectly on my N800, BUT I don't know if it is a result of the N800 update or the RR webmail update!

RR had advised earlier that a new version of webmail was being rolled out and we would be alerted to the change when applicable to our area. Well, it was the old webmail interface yesterday (looked like your woh interface linked above) and today, unannounced, I get the new interface at my link http://webmail.triad.rr.com. So there may be hope for you if the improvement was due to RR webmail update.