I am trying to install Windows 7 64 bit on my Mac via Bootcamp, only problem is that its an .iso file, and every time I mount it or burn it and click install Bootcamp can’t find it.
When burning an ISO you must make sure that you aren't simply writing a single somefile.iso to the CD, but rather giving the ISO to the CD burner as an image of the CD.
If this is the problem then here is a nice simple guild on how to burn an ISO from a Mac. http://www.macosxhints.com/article.php?story=20060619181010389
If not please comment and we'll go from there.
I'm interpreting this question as being a problem with the .iso not being recognized by the wizard function within bootcamp (when it asks to create a bootable USB Drive from the windows .iso) (btw, win 7 isos are available for direct download from MS at - http://www.techverse.net/download-windows-7-iso-x86-x64-microsofts-official-servers/)
I encountered this same error and the solution was to copy the .iso to my documents folder instead of the external drive I had originally downloaded it to. Wouldn't even work from the Desktop, but as soon as I copied to my Doc folder, voila!
NOTE: You also Seem to have to download the ULTIMATE version of 64-bit Win 7, regardless of which license you have or intend to install as the smaller versions are missing key drivers, (which will show up in the next step) even if BOOTCAMP assistant accepts them as 64 bit and they are in the right place (Documents).
Probably no help to OP, but hopefully will help others.