Classic symptoms of conflicting or incompatible custom content.
See here (especially regarding the time consuming but tried and true 50% method):
http://www.sims2wiki.info/wiki.php?title=Game_Help:Finding_Problem_Custom_ContentYou might try, if you are able to determine the items by date, temporarily removing your latest installed custom content first in working on ferreting out the troublesome files.
Note also that you may have custom content installed which you weren't aware of -- custom lots can potentially include unwanted, unecessarry or incompatible hacks or hacked objects which can be installed along with the custom lot.
Both the Hack Conflict Detection Utility and Clean Installer can be helpful in determining what you have installed or even what potentially may be problematic.
HCDU at:
http://simwardobe.com(Sims 2--Programs)
Clean Installer:
http://sims2pack.modthesims2.com/index.php?page=3.