F4798w85gasdg,
I believe you need an IIS virtual directory set up if you're looking to browse files in the "_SharedFiles" folder, because it is outside of the "somesite" folder. ColdFusion mappings only allow ColdFusion to see resources outside the web root for tags and functions like <cfinclude> and CreateObject(). They don't allow the web server to access those locations. Virtual directories in IIS allow you to browse to locations outside the web root.
-Carl V.