BiSixToy Cliassi

I can log in with my Alts but just not my main Avatar, logging into SL Web page is fine, so my name and password are not compromised. The message I get is Internal Server Error But it is only with the one Avatar. Alts log in no problem. I have also tried it on several PCs and Laptops and 4 different viewers. This sounds like a problem for Linden techs but how do you contact them????