I've searched as extensively as I can and the only solution is a broken thread in the recesses of these forums. I get a message during setup (usually right around MenuVoices.bsa) saying: C:\Program Files (x86)\Bethesda Softworks\Fallout 3\Data\Fallout - MenuVoices.bsa doesn't match the file in setup's.cab file. The medium from which you are running the setup may be corrupted; contact your software vendor. I get a catastrophic failure if I click "Retry" and setup closes. Every subsequent file gives the same error message if I click "Ignore" and setup fails. Any ideas????

I am having the exact same issue.

I chose 'Ignore' and the installation appeared to finish properly and there is a 'Fallout - MenuVoices.bsa' file in the correct directory. It is ~31mb, can someone confirm if this file size is correct?

I am yet to try starting a game, I am hesitant as I have read reports of people with this error failing to get past the Birthday part in Vault 101.

I will try and report back.

EDIT: Game crashes at the first dialogue with Amata.

Ok, well I've fixed the problem.

The installer was unable to properly extract the file during install, whether this is due to bad media, either damaged or not pressed properly in the first place or a clash with my hardware or software or something else completely.

I attempted to manually extract the file using several unzip/extraction programs, all threw up errors.

I was able to use 'InstallShield CAB File Viewer' to extract the individual file from another copy of Fallout 3 (Vanilla) I had and manually copy it to the Fallout 3\Data directory.

FYI, the error occurred whilst attempting an install with a 'Game of the Year' disc.

You have a bad disc. Take it back to where you bought it and have them replace it.

Perhaps, and I plan to.

I'm not the only one with this issue: http://goo.gl/DuSB