The good folks over on the Operations Manager product team blog just posted a heads up on an issue you might run into where SCOM 2007 setup fails to detect SQL:
If you have run into issues during setup where you know that you have a supported version of SQL running on your machine but setup in unable to detect it, you may have hit a SQL WMI provider issue. In OpsMgr 2007 R2, this shows up as the SQL Server requirement in the Prerequisite Checker failing.
Setup calls WMI in order to check SQL version to determine if the SQL version meets the prerequisites. Once you have verified that you do in fact have SQL installed on the machine and that it is indeed a supported version of SQL, check if the WMI provider is the the issue by trying to connect to SQL using SQL Server Configuration Manager. You should receive an error that reads:
"Cannot connect to WMI provider. You do not have permission or the server is unreachable. Not that you can only manage SQL Server 2005 and later servers with SQL Server Configuration Manager. Invalid class."
For all the details and the solution see their post here.
J.C. Hornbeck | System Center Knowledge Engineer
The App-V Team blog: http://blogs.technet.com/appv/ The WSUS Support Team blog: http://blogs.technet.com/sus/ The SCMDM Support Team blog: http://blogs.technet.com/mdm/ The ConfigMgr Support Team blog: http://blogs.technet.com/configurationmgr/ The SCOM 2007 Support Team blog: http://blogs.technet.com/operationsmgr/ The SCVMM Team blog: http://blogs.technet.com/scvmm/ The MED-V Team blog: http://blogs.technet.com/medv/ The DPM Team blog: http://blogs.technet.com/dpm/ The OOB Support Team blog: http://blogs.technet.com/oob/ The Opalis Team blog: http://blogs.technet.com/opalis