(Update 09.04.2014) Ok, need to update this information!
This last month I decided to reinstall Sims 3 since I have a new CPU. I played smooth all this time, but now I got into save freezing problem again. I tried the method I learned before, but with no victory. I couldn’t save my progress because it keep saving, but actually doing nothing. So I searched into the matter again and I found THIS info which seems pretty cool and worked for me.
Sometimes, when I tried to save my game, the saving screen appears, but it looks like it’s going on forever. That’s why I wasn’t able to progress with the story. I also searched throughout the web for a patch or fix, but nothing worked. Until I found this comment below which came with a solution that made me to be able to save again:
„… I noticed in my saved game folder there is a .package file for each .nhd file. This does not exist in a new saved game (with the exception of the TravelDB.package). I moved the .package files to my desktop (again with the exception of the TravelDB.package) and ran the old saved game. My save attempt worked! I have no idea why so if you could provide me with some information on that I would greatly appreciate it. hope this helps someone else!”
Hope this note will help other simmers as it helpled me!