This is just a note to let FIM 2010 Rollup 2 users know about a rather important, but also rather obscure, article.
After applying FIM 2010 Rollup 2, and following the instructions in http://support.microsoft.com/kb/2635086 - your first .NET supportedRuntime element in miiserver.exe.config will be NET v4.
However, this makes it impossible to create a new FIM Service / Portal Management Agent, which will always fail with a vague error about connecting to the database or to the FIM resource management service, or failure to retrieve the schema.
The fix is to reorder the supportedRuntime elements so that NET 2 comes first: http://social.technet.microsoft.com/wiki/contents/articles/9112.troubleshooting-failed-to-retrieve-schema-or-cannot-connect-to-database-while-creating-a-fim-ma.aspx
Needless to say, this had me stumped for a good while -- double checking my firewall rules, SPNs, etc., granting unnecessarily high privileges to the FIM MA account, etc., etc.