how to fix invalid class string

[LadyWhite Farrior]

i have this message as a error when i try to sign on to sl  i have no idea how to fix that ... 

i have updated pc, took off and redownload sl. restart pc .. this is the final thig it say invalid class string 

can anyone tell me how to fix this please thank you 

leave this here for others  i fixed the problem  you need to delete all of sl on your pc including your roaming an such  take off sl and redload and then restart pc and and redown load good luck all 

[LadyWhite Farrior]

more information so you can help it say after i run check to see whats wrong

the xml page cannot be displayed

cannot view xml input using xsl style sheet please correct the error and then click refresh , or try again later 

 

invalid class string