Hi guys,
This seems to be an Internet Explorer "thang" (I personally shy away from IE and prefer Mozilla's Firefox).
I went looking in the vBulletin user forum (our forum software), and according to the developers, Internet Explorer 11 has a bug where it does not correctly name a file when a php script is used to fetch the file - it ignores a header which specifies the filename and type. No idea if MS will fix it sooner or later (or at all). I tried Internet Explorer 8 on my one machine and the download worked fine - no "php" extension.
So sorry guys - nothing we can do here. And have I mentioned lately how much we love Microsoft
ttfn,
Sherry