An access violation is when a program attempts to access a specific memory address in a way that's not allowed, for example reading from a location that was not designated to store data for that program. Windows then detects the violation and shuts down the program.
The issue is in trying to figure out the cause of that violation. It's not Sims 3 itself, unless the install is corrupted, since the game runs well, or well enough, on most systems. Normally, the next places to look would be the libraries that Sims 3 uses, so VC++ 2005 (you reinstalled it already), .NET Framework 3.5, and DirectX 9. But the fact that the game runs fine vanilla makes it less likely that any of those are the issue, or for that matter the driver for your graphics card.
There's still a possibility that the content you're adding to your user data folder is corrupt and causing the issue. If you haven't already, please try downloading a fresh copy of one file and installing it into an otherwise clean folder. If you still can't play, disable any antivirus/firewall you have running and try the same thing. If that doesn't work either, take your computer completely offline and try again. You can sign into Origin and put it in offline mode, then disable wifi and/or pull the ethernet cable.
If none of this helps, please create a new admin user account on your computer, and try the same thing in that account. (You can skip right to the step where you play offline.) That's the fastest way to test for permissions issues and other problems with the specific user account.
While testing, it's always a good idea to run Origin and Sims 3 as an admin: right-click on the .exe or a shortcut, select "Run as administrator." At the very least, it won't do any harm.
