I migrated report server from 2003 OS/SQL 2008 32 bit/IE6 to 2008 SP2 OS/SQL 2008 SP1 64 bit/IE 8 and had some difficulties. But I think I've got it in a place I could edit the data source and get it all working IF the web page GUI would let me.
The new server is shown on left but I don't know what to do to IE or whatever to get the GUI so that I can work with it like it was on the "old" server (shown on the right).
The servers are in a manufacturing environment and the customer doesn't keep software like IE current. They prefer to keep things functional rather than risk breaking something with software upgrade. This was mandatory to get off the 2003 OS.