VERY WEIRD attachment problem, error is "invalid attachement specified" w/ screencap

[Protonus]

I recently took over administration of a local forum. This has been going on for a while but may have been occouring since update to 3.6 (maybe even 3.5). Any attachement you click on, on the forums gives you an "invalid attachment specified" error.

What is VERY odd, is that the page it displays, is from THIS forum, the Vbulletin.com page! Even more weird in the upper right it says "welcome Brent_strong" which is the username of the OLD administrator we had and his account on both our site and this site. The style isn't even the one we have as default or are currently using But the URL shows ourpage! I am at a complete loss here.. here is a screen capture of the error:



I have tried using the default style, disabling all products and plugins, and it still does it. If a customization is to blame, I don't know how else to check for modifications to the board other then plugins/products/styles...

Our board was originaly 3.0.X then 3.5.4 and now 3.6.0 if that helps any.

finally fixed this. Ended up being an incorrect/damaged/whatever attachment.php file in the forums root. I uploaded a fresh one from a new install of 3.6.0 and it fixed it. This can be closed or whatever.