April,
You might have better luck by first moving or copying your CD file onto your hard drive, and then trying to open it with your password. CD's behave "funny" when you try to interact with the files stored on them, such as responding to a password prompt. Remember, the "last name" of CD is "ROM", standing for "Read Only Memory."
Try it from the hard drive. And if it almost works from there, except it makes you open a "read-only" copy, accept that offer, and then immediately "Save-as" a slightly different filename, and the "read-only" quality will be defeated.
HTH /s/ Larry