Wasted my SharePoint Administrator half a day to debug something that was my fault. Sorry Dave!
The search site(Standard SharePoint) uses minimal.master as the Site master page(In SPD, choose Set As Custom Master Page) and uses v4.master as the System master page(In SPD, choose Set As Default Master Page)
To customize the master page on search site, make copy of minimal.master and DON’T change v4.master as the DEFAULT MASTER PAGE!!