I have tried this a couple of times and every time I do it i pull my hairs of and say how did I installed SQL 2005 Reporting Services on Windows Server 2008 again?
Oh and why am I still using SQL 2005 on some machines? I need to remember this script and never to ever search for it again.
Ok, before proceeding, check out the SQL 2005 Requirements via TechNet: http://technet.microsoft.com/en-us/library/ms143506(SQL.90).aspx and other SQL related troubleshooting here: http://technet.microsoft.com/en-us/sqlserver/default.aspx
Here we go, and actually its very easy just run this scripts:
For 32 bit :
cscript %SystemDrive%\inetpub\AdminScripts\adsutil.vbs set w3svc/AppPools/Enable32bitAppOnWin64 1
For 64 bit :
cscript %SystemDrive%\inetpub\AdminScripts\adsutil.vbs set w3svc/AppPools/Enable32bitAppOnWin64 0
After the script finishes, it says True (Bool) then thats it, run your installer again and off you go.