Not really a AL problem, but since I have that installed.......
Got the Sims2 for Christmas, now (like an idiot) have all the ep's and sp's....
Some of the problem I think is that I am addicted to downloads, doesn't matter the game, just love adding custom stuff.
From the very first, (which was Double Deluxe) now replaced with the base game as a starting point, it will be acting fine and then all of a sudden I can't place objects on walls.  Oh I can paint or wallpaper the walls...but nothing else will attach, not lights, windows plumbing, pictures, you name...won't take them.....and no furniture or anything else over 1 tile wide can be placed next to the walls either inside or outside.  
I have uninstalled many times ( so much so that I knew the original games serial number by heart).  I tried everything that EA customer support would suggest...have now become an expert at deleating everything in the compter that relates to the game.
I thought it might be the Inteen mod....because when I have installed that...the Sims will just stand there and not interact with each other in anyway..... I thought it might be ACR (which I really like)....I've thougth it might be the SimBlender which is my favorite of those types of mods....but with them out ..... nada....still have the same problem.  Have deleted and lost many add ons,  
The reason I'm here is the fact that I deleated it all again today and am just not up to the task of reloading everything again and starting one cc at a time...... because if I do find out it is just one simple package causeing the problem....well when I find that problem...will have to remove everything again and reinstall..
Oh, have also used the clean pack installer and have now gone so far that if something comes up any color highlight at all, it's gone.....
I'm really stumped on this and EA is no help at all....if anybody has any majic words or a new train of thought would love to hear from you........it hurts to go through an hour or so of deleating then more time installing and not being able to use the game as it was intended....

By the way I'm using Vista on a fairly decent machine with a middle of the road graphics card that runs everything else well.....

Help....
And thanks in advance...
Duane

OH...and something else i should mention...every time I go into a lot..... I get the popup that says object error..... won't go away with  retry or cancel ... just deleat... and the  error reports mmmmm I don't know how to read them...