In order to fix the issue, use Google search engine to find and download CFF Explorer. After that, navigate to (C:) > Program Files (x86) > Electronic Arts > The Sims 3 > Game > Bin, right-click on the TS3W.exe file, press Copy and then paste it somewhere safe on your computer to create a backup. After that, launch CFF Explorer and from the File menu select Open. Browse for the TS3W.exe file, select it, press File Header and then Characteristics from the right. After that, press the blue Click here button, check the App can handle >2GB address space box, click OK, save the file from the File menu and overwrite the file.
If this doesn't fix the error, remove the tool from your computer, run CCleaner or Glary Utilities to make sure that there are no leftover registry keys in your system and install it again.