Using PortableWinCDEmu-3.4, the ISO mounts but does not assign a drive letter. Note: the ISO is a local file, not a network drive (was actually on a network, but I made a copy to my desktop).
I then installed the latest version of WinCDEmu (non-portable) and despite specifying the drive letter, the drive does not mount under that letter. I even had a Blue Screen of Death the 1st time I tried to mount it.
There is no problem with the ISO as I could mount it all right on a 64 bit Windows 7, using PortableWinCDEmu-3.4.