There seem to be a couple of issues with some libraries referenced in 5.3 when you run those libraries on an 64-bit environment. A while ago I heard about a trick which would allow you to run IIS in 32-bit mode, even when the OS is running on 64-bits. Today a partner called me with the exact same question. So I’ve redirected this person to the knowledge base from Microsoft: How to switch between the 32-bit versions of ASP.NET 1.1 and the 64-bit version of ASP.NET 2.0 on a 64-bit version of Windows
I haven’t found any time to test it. So all experiences are welcome!
Update: The partner just contacted me and told me it’s working. Of course both them and we don’t recommend such a solution. But in some cases you simply have no choice. Thanks for sharing.