SQL Install fail

Hejsa

Jeg har en SBS2003 server.
Denne har Microsoft SQl installeret

Nu vil jeg så gerne installere Symantec Backup Exec.
Problemet er at denne fejler når den skal til, at installere "SQL Express".

Fejlen i "Event viewer er":

Product: Microsoft SQL Server Setup Support Files (English) -- Error 1731. The source installation package for the product Microsoft SQL Server Setup Support Files (English) is out of sync with the client package. Try the installation again using a valid copy of the installation package 'SQLSUPPORT.MSI'.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.