Adam, the 404 is returned by IIS of course, since it does not get the correct http path returned from CF10 via the custom cfm that throws the cfincludes and makes it create the object for us.
Also, the ACL's are 100% exactly the same on the CF8 server as the CF10 server, same domain accounts are used for the different app pools, site roots etc. , always using a checklist for all these things regarding IIS and CF.
On the IIS servers that run with CF8 there are no such things as Virtual Directories, heck, CF8 itself doesn't use even need to add these CFIDE and jakarta vdir's for all sites like it does with CF10.
Disabling the mapping on the CF8 servers does make the cfinclude/create object fail btw.
Site A has a root, the application cfincludes and creates an object from another root that is mapped into CF, CF10 doesn't seem to understand UNC mapping at all, it even uses unix format instead of keeping it to Windows, so it just adds the UNC path to the URL instead.
I even tried with quad and double slashes to make sure that it wasn't CF's tomcat apache that missed some escape sequences, still doesn't work.
Maybe I explain this wrong, but what used to work is broken.
Almost feel to setup a new Railo4 server just to see how it works with the fixes they added lately.
Reminds me, we got another little web cluster where we run Railo3, which also has an underlaying Apache Tomcat.
There the global mapping works flawless as well, no need for adding an IIS vdir for the ShareFiles folder, exactly the same way as it does work with CF8.
