EP 6.0 Installation error on MS SQL Server

Hi I try to install EP 6.0 from

https://www.sdn.sap.com/sdn/downloadarea.sdn

and I get an errormessage during the installation

ERROR 2004-12-10 13:39:16 MDB-05042 Error when executing script "if

(exists(select name from master..syslogins where name = 'SAPJ2EMM')) exec sp_droplogin 'SAPJ2EMM'"; error: "[Microsoft][ODBC SQL Server

Driver][SQL Server]Login 'SAPJ2EMM' is aliased or mapped to a user in

one or more database(s). Drop the user or alias before dropping the

login.". ERROR 2004-12-10 13:39:16 MDB-05034 Call to a threaded

function returned "4". Could somebody please help me? Regards Frederik