missing characters

I often use my friends guild wars account, he has two and I know the info for both of them. Today I went onto one of the accounts and had no problems, but when I went to go on the second account there were no characters (there shouldve been 4) and when I selected the create option it said the account wasn't authorized to play guild wars and asked for the key code. I have searched forums on multiple sites extensively and can't find anything like this. Any suggestions would be greatly appreciated!