I have a similar OWA problem with IE8. I have a handful of remote
users who recently upgraded to IE8 and now they get the "Loading"
prompt. I have delt with the "Loading" prompt before, being related to
permisions on the exchange virtual direcotries in IIS.
I was sent a screen shot of an error:
Invaild procedure call or aurgument
These are the only users having a problem, they can access their
accounts just fine with chrome or firefox. I have even tried OWA on
IE8 and could not generate the same results.