Metal Gear isn't, i can load it fine from the d without any extra work. Anyway, the iso might be screwed, wich program did you use to make it? I suggest alcohol120% or clone cd (both using the .ccd format).
Regarding cd's try with peops cd-plugin, select aspi read mode if youa re using win9x/me, or ioctl scsi if you are on win2000/xp. Configure the drive, let it auto detect the read mode, and choose async read if aspi, thread if ioctl.