Error while trying to attach .mdf to a SQL Server Express 2008

The snapshot says is it all - I used to be able to attach a dat开发者_运维百科abase, but after i detached today then tried to attach, i kept getting this error:

http://img197.imageshack.us/img197/2574/attacht.jpg http://img197.imageshack.us/img197/2574/attacht.jpg

http://img197.imageshack.us/img197/2574/attacht.jpg

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Error 5 means Access Denied. The account running SQL Server has no access to the file GMATech.mdf. Grant the necessary rights:

cacls "c:\Program...\GMATech.mdf" /E /G SQLServerMSSQLUser$<hostname>$<instancename>:F

where hostname is the name of the mahcine running SQL and instancename is the name of the SQL instance (MSSQLSERVER for default instance).