delete admin account have delete admin panel acces

Hello, I have a strange problem: I have a Worpress MU (2 blogs). I had not yet changed the default account (admin). So I do, I created a new account, I disconnect the main account> I connect with the No. 2 Account> and I delete the account # 1. But now I no longer have access to the administration of the blog # 1 !!! Blogs are available in fronthand. An idea ? Thank you for your help.