Okay, so I was planning on adding some dive lots into my WIP world but then I remembered reading from somewhere - I think it was back in the official forum but I'm not sure - that adding lots in EIG with the lot tool will eventually cause corruption in the world; that the lot tool is bugged somehow. I tried to find the thread about it but couldn't, so could someone tell me if it's true? And it is, is it fixed by now? Thanks.

From my experience - place the lot, then after saving and exiting Edit in Game, saving and exiting CAW, just clean the global layer after.
Anytime I touch a lot in CAW/EIG, I clear all Sims 3 and CAW cache files and clean the global layer after.

You mean like this: http://www.modthesims.info/showthread.php?t=473791

Seems like quite a bit of work after every single use of CAW+EIG.

If you're forced to use the more detailed process of cleaning the global layer, consider, you need only do it once, from that point on you have a clean global layer to copy and paste.

Just wish Maxis had spent the energy to make the Sims3 bug free before walking away from it to pursue new versions.

Ah, okay then. I'll do that. And about Maxis... yeah, I totally agree.

Are you laying down lots repeatedly? If so, yes, it will corrupt the CAW files. CAW don't like. You have to clone lots in CAW, not put the same lot in EIG. CAW will not recognize it because I believe it assigns an ID for each new lot so repeat lots in EIG will cause it to freak.

No, I am not placing lots repeatedly. And I've been building this world over year and half now without any problems with lots. The question was about the game's (not CAW's) own Add New Lot -tool which I haven't really used. It was said to be glitched.