Okay so, I've tried downloading BOTH different patches separate times to get this game to work (I'm receiving the 15MB error) and for the life of me, I can't get it to work.
 
Am I supposed to replace the steam files with the patch downloads?
 
Am I supposed to just add in the Extras folder in the Steam folder? 
 
Nothing I've done short of turning off my ram (I refuse to do that regardless) has worked. I'm pretty close to calling Valve and getting a refund.

If you find the vampire.exe (or whatever it is called) in your steam directory. Right click > properties and set it run in Windows 7 compatibility mode then run it from Steam it should work.

That is how I got it to run yesterday and I assume you are running 64-bit?

Give us more details of what we're working with. Specifically your OS. Back when I got it working (I had a retail CD) it was a pretty convoluted process, but I also downloaded the large mess of community patches beforehand.

sounds like you just patched it wrong, because it tosses in the extras folder in your vampires directory when you patch it correctly.

@Bobby_The_Great: Hmm, well try it with XP 32-bit then. See what happens.

http://www.patches-scrolls.de/vampire_bloodlines.php
 
download the latest build of unofficial patch. And set the .exe to XP sp2 comapatibility, and run it as administrator.
 
If you have more than 3gb of RAM you might have to disable some in MSconfig "unless the steam version has this fixed"
 
EDIT: silly me for not reading your post. Disabling RAM is the only way. Demand a refund or suck it up, I'd say the latter becauuse the game rules.

You are installing unofficial patch 7.6 correct?
 
When I did it I installed the patch to the steam/steamapps/common/vampire the masquerade-bloodlines/    folder. 
 
Also, I notice there is an install64 exe in the extras folder. Have you tried that? 
 
I managed to get this game working a few weeks back but for the life of me I can't seem to remember what I did.
 
I think you also need to disable the automatic updates for the game on steam.You could also untick the "enable steam community in game" box.
 
Edit: This post is so disjointed!

Here we are. I went through my browser history searching for what I did.
 
You need to download this.
 
Right click. Run as admin.
 
Click the "..." button and navigate to steam/steamapps/common/vampire the masquerade - bloodlines/Bin/ engine.dll 
  Make sure the make a backup box is ticked and then press start.
 
Hopefully this should fix it. If the game starts you should also be able to tell if you have installed the unofficial patch correctly because it will say something in blue at the top left of the character creation screen.
 
Also, you will probably have to go the extras folder and use the ResPatch.exe so you can use higher resolutions.
 
Get back to me if this works.

I have no answers for you, but I wish you the best of luck getting this to work, because it's a wonderful game that everyone should play.