One thing I found, at least for the version 4.6.17, is that when we went to install it on a 2003 server that was fully patched/updated, we had issues. The problem was .NET 2.0 Might not be an issue on every system, but for us it was becuase .NET 2.0 was up to SP2 and I think the installer for 4.6.17 is expecting a plain-jane .NET 2.0 with no service packs. We had to uninstall all of the .NET updates to get back to a basic .NET 2.0, Install the product, and then we could update .NET with the latest patches/Service Packs.
Just something to consider. I'm hoping it was isolated to us ;-)
Brian