To sum up, gamesas have been bundling third party mods in with the recent batch of fallout re-releases. One of the included pieces of work is an application of mine by the name of sfall. It's something that runs alongside fallout to provide middle mouse button support and other similar tweaks, and is usually only targeted at people who know what they're doing with it. Rather than being a mod in the traditional sense, it contains executable code that overwrites parts of the fallout exe at runtime in a rather untidy way, which can cause various problems which would be very hard to track down for someone who doesn't know what's causing them.
The mods that gamesas have been including are all effectively stolen. None of us authors have been asked for permission, or were even informed our work was being used. I only found out about it when people started googling some of the error messages they were getting and tracking me down, which was not a very pleasant way to find out what was going on.
So, in the hopes it will save some people a bit of confusion, (and me from receiving a few more irate emails,) here's a list of all the most common sfall-related problems you're likely to come across and what you can do about then. I'll add any more as I think of them. Most of these involve modifying ddraw.ini in some way, which is a file sfall adds in the main fallout folder. If it isn't there then you don't have a copy of fallout that bundled sfall, and any problems are coming from elsewhere.
On startup, fallout crashes with a 'Failure initializing input devices' error.
In ddraw.ini, in the [input] section, change BackgroundKeyboard to 1 and see if that fixes the error. If it doesn't change BackgroundMouse to 1 too.
Black screens/psychedelic colour schemes.
Both problems can happen without sfall, (especially on vista/win7,) but sfall can make them happen on occasion when they wouldn't otherwise. To fix it, in the [Graphics] section of ddraw.ini change Mode to 4 or 5.
Corrupted movies
Edit: Looks like none of the distributed sfall versions were actually old enough to suffer this bug, or at least the ones that were are no longer being sold, so hopefully it's a non-issue.
Edit2: Or since I've just had a report of it, maybe there are... No way for me to know for certain, I suppose.
This is a bug in the version of sfall that gamesas have been including. If you get corrupt movies, you'll need to set Mode in the [Graphics] section back to 0. If you can't because of the black screen problem, you'll need to update sfall to the latest version. (Unless you bought fallout on steam, in which case you can't manually update your sfall version, and are out of luck.)
Random in game crashes with compatibility mode turned on, or you get an error message about fallout running in compatibility mode on startup
sfall doesn't play nicely with any compatibility mode settings. Turn them all off. Sometimes sfall will pick up on compatibility mode settings and display an error on startup instead of getting in game for a bit before crashing out. If you're on vista/win7 and get the 'you are trying to run fallout in compatibility mode' message even if you aren't in compatibility mode, you'll have to update sfall.
The world map stutters horribly, or the rate of random encounters is insanely high
In the [Misc] section of ddraw.ini, make sure WorldMapFPSPatch, WorldMapFPS and WorldMapDelay are all set to 0.
Fallout crashes on startup with a 'You're trying to use sfall with an incompatible version of fallout' message box.
You've probably just downloaded a no-cd patch or done something else to modify your fallout exe. sfall requires a specific version of the fallout exe, and will whine at you if you try using it with anything else.
A crash on startup mentioning a missing entry point in kernel32.dll
Despite the supported versions of windows list on the back of some of the trilogy box including 98 and ME, the version of sfall they include only works on xp and above. You'll have to download the win 9x version and replace the bundled version with it. On the other hand, the loading mechanism used by sfall doesn't work reliably on win 9x. If you're using a 9x version with a fallout release that bundled sfall and aren't seeing this error, then sfall isn't running at all, which will cause problems later on. (See below)
Your virus scanner picks up the fallout exe and/or ddraw.dll as a generic virus
This is caused by the proactive defences side of the virus scanner noticing that fallout is displaying suspicious behaviour. Either turn behaviour anolysis down/off, or add the fallout folder to its exclusion path. It's not a false positive as such, because sfall does indeed pull some stunts which would look suspicious to a virus scanner. (i.e. self modifying code, and overriding the normal search path to hook a system dll.)
Windows explorer hangs, consuming 100% cpu time
Fallout crashes on startup with an error about directx not being installed
Not actually an sfall bug, but a problem with the way windows parses dll resources when you're using a multibyte character set. You need to be using a multibyte MUI like Chinese to trigger this one. Viewing a folder containing sfall will lock up windows explorer, and when running fallout it will be unable to load sfall's ddraw.dll causing it to assume direct x isn't installed properly and display that error. I had attempted to work around it in newer sfall versions, but it seems to have reoccurred in the 2.0 releases. At the moment, there would seem to be no solution except to remove sfall. (Or switch languages, of course.)
Another obvious answer to many of these problems is to just remove sfall. In your fallout directory, getting rid of the files 'ddraw.dll' and 'ddraw.ini' will suffice. The problem with doing this is that sfall isn't the only 3rd party work that gamesas have been stealing; for fallout 1 it's fine, but in fallout 2 killap's patch has been included too, and some of the scripts in it depend on sfall to work correctly. Without it they will crash, with possibly weird effects. (It's unlikely the whole game will crash, rather you will find quests and the like just stop at some point.)
And of course, I'd still welcome any comment from gamesas staff. It's bad enough to steal someone's work in the first place, without ignoring your victims afterwards. You owe at least 11 people an apology and a seriously good explanation.
Oh, and another final thought for everyone whose been unknowingly using sfall; gamesas don't have the sourcecode to the version they've been bundling, and have no way to check if it contains any malicious code. I hope you all trust me.
Edit: Important note for vista/win7 users
Something else I forgot to mention; since the ddraw.ini you need to modify is in the fallout folder, if you've installed fallout to its default install directory in programs files you wont be able to edit it. (Seriously, don't install pre-vista software to program files, especially any games. They always ends up biting you in the face.) If you try, you might get an error when you try and save, or it might appear to save successfully but no changes will show up in game. (Or, if you have the correct magic combination of run-as-admin flags, it might work, but it's risky.) Rather than editing ddraw.ini where it is, copy it to your users folder, edit it there and then copy it back.