you were right all the handlers for the owa were pointing to the 32bit asp.net.
I manually changed all the handlers to the 64 bit (is there a quicker way) for owa.
The global handlers (default for the website) are also pointing to the 32 bit handlers.This is probably because I migrated my website from a 32bit iis6.0 to iis7.0 first.
How should the setting look?
Anyway this was not enough as the error I'm now getting is
Server Error in Application "DEFAULT WEB SITE/OWA"Internet Information Services 7.0
Error Summary
HTTP Error 500.0 - Internal Server Error
There is a problem with the resource you are looking for, so it cannot be displayed. Detailed Error InformationModule IsapiModule
Notification ExecuteRequestHandler
Handler PageHandlerFactory-ISAPI-2.0
Error Code 0x8007007f
Requested URL https://www.halinasplace.com.au:443/owa/auth/logon.aspx?url=https://www.halinasplace.com.au/owa/&reason=0
Physical Path C:\Program Files\Microsoft\Exchange Server\ClientAccess\owa\auth\logon.aspx
Logon Method Anonymous
Logon User Anonymous
Any suggestions?