I followed the instructions to the letter, and the first time I opened the launcher from the working launcher folder it worked perfectly. Everything I tried installed perfectly with no problems. Since then, every time I open the launcher from there, previously installed files show up properly and new download files are recognized, but they won't install. The launcher seems to consider opening the files, but never does. Instead, a black box the size and shape of the initial installation box shows up and, after processing for a moment, just disappears. After that an exception file appears in the ...My Documents\Electronic Arts\The Sims 3 folder.
Does anyone have any idea why this might have happened and/or how to fix it?
In the bin folder, there are S3Launcher and Sims3Launcher App files. When I was using the first one, I encountered the same problem as you. Make sure you are using the second one. I hope that helps.