OKAY i am extremely fed-up with sims CAW with ruining my files. Every time i create a world it shows this dang " a serious error has occurred on so and so. world and it is highly recommended that you restart your game!"
i swear i would gladly punch my computer screen because it's the fifth world thats been screwed up by sims. It isn't any of the worlds that are already in the game or downloaded from another person it only seems to be the ones i've made. I'd REALLY appreciate it if someone can fix the file, or, tell me how to fix it. I have already deleted cache files and restarted the game all the usual things and non of it seems to work. The world is large and i just want to use it for an equestrian center but, im having a problem as I've already stated.

PLEEAASE HELP ME!!

Not much to go on. Is it an imported world? A world made in CAW? What mods do you have? I have had better luck in creating a new Windows user, and running CAW from a clean user file with only the essential CAW mods; NRAAS porter, Master Controller and master controller cheats.

What were you doing when it crashed? EIG? Saving in EIG or in CAW?

Might be better to ask in the CAW forum.

There is lots of troubleshooting ideas in the caw forum, if you ask you might not get the right answer. There is so much history of crashing caw and the solutions are as many as the people answering often. Here is a troubleshooting guide: http://www.modthesims.info/showthread.php?t=441595

When does this error occur?

I sometimes got this error when loading a game (not CAW) if I have opened the Sims 3 folder in the file explorer (windows) no matter which world. So, closing all explorer windows (to be on the safe side) before loading has erased that error for me.