Error trying to install management pack

I am trying to install the F5 Management pack.

I am seeing this error in the log:

<10-23-2012 11:57:08> Info: Installer stage: Sql.Database STARTING

<10-23-2012 11:57:08> Info: Installer Stage[Sql.Database]: action=Custom Install Action: Install, duration=00:00:00, state=Starting

<10-23-2012 11:57:12> FatalError: Unable to create database[Server=SqlServer,Database=F5_ManagementPack] due to error: Login failed for user 'INTERNAL\sl088a'.

<10-23-2012 11:57:12> Info: Installer Stage[Sql.Database]: action=Custom Install Action: Install, duration=3.7sec, state=Success

<10-23-2012 11:57:12> Warning: Installer stage: Sql.Database FAILED

During the installation, I supplied the credentials for the SQL server database instance which was INTERNAL\scom_msa_dev, so I don't understand why it is carrying the user credentials from windows when it is trying to do it's thing at the SQL server end.

I am logged onto Windows Server with a domain admin account, which does not have access to the SQL server database instance.

The SQL server credentials that were supplied during the installation dialog panels do have access to the SQL server instance.

Is it really necessary to logon as a domain admin, that also has an account on the SQL server instance..??? I would have thought the purpose of supplying the credentials during installation would mean that would not have to be the case.

Can anyone help...??