Do any of them show up? For some people, if they download/install several lots at once they then find only the last house that they installed in their Lots & Houses bin.
You said you have successfully installed clothing, hair and other stuff so I take that to mean that you already know that you have to extract files out of either a zipped or a rar file before you can actually install them. Lots are the same way.
They are first packaged in a Sims2Pack (that happens in the game and is the only way you can get a house out of the game) and then further compressed into either a zip file or a rar file. So, after you download the house you want, you must extract the Sims2Pack file out of the zip or rar file before you can double-click on it and choose install. But, based on the fact that you know how to get other items (from MTS2, right?) into your game, then I'm going to assume you know all that and that's what you did.
First, I'm going to tell you that because you have EA's newest game, Free Time installed on your computer, you should be able to put any house into your game. Even if that house has items from an expansion pack or a stuff pack that you don't have installed, you still should be able to put the house into your game. You may find that a wallpaper is missing or a flooring is missing because the creator used a wallpaper or flooring that was from an expansion or stuff pack that you don't have installed, but you still should be able to get the home no matter what. The only time you run into a problem due to not having one of the expansion or stuff packs is if you try to put a house that was made in a game that has newer expansion or stuff packs than what you have in your game. I only have up to Celebrations stuff and I play with my Seasons disk installed. If I tried to put a house you made into my game, it wouldn't work because Free Time and Teen Style stuff are both newer than the games I have installed. Because you have Free Time, that means that every lot should work.
Have you ever installed the Sims2Pack Clean Installer? There are times when you can't get a house into your game, but if you use the clean installer to open the lot, it will then go into your game. Here is a link for the clean installer:
http://sims2pack.modthesims2.com/index.php?page=3
If you download and install clean installer then here is what you have to do to get it to open the lots you download. Save the lot to your computer. Now right-click on it and click on Open with...then browse to where the clean installer is on your computer and choose it. Make sure the little box that says something like "Always open with this program" is checked.
If you still cannot get them to show up in your game after doing this, there is one last thing you can try. I ran into another simmer who had tried everything and nothing would work until she found some really hard to find instructions. I'm going to copy and paste her post to my guestbook for you to read. The reason I am is because not only is the link to the help in the post, but also she explains that even with that help, she first had to do something else and in case you run into the same thing I wanted you to have this information to read. Here is her post to me:
<<
http://www.modthesims2.com/wiki.php?title=Game_Help:GCCTSU9
But it took a bit more than just a force install to get the lots to show up. Remember how nothing was in my teleport folder? Well every time I installed a lot with clean install a pop up kept coming up saying that the file already exists. I thought to my self 'It's not in the teleport folder, but it exists...' So i did a computer search (I typed in the name of the file) and the two files showed up. I moved them into the teleport folder and did a force install from there.
So if somebody had the same problem as i had (god forbid), then they would have to search up the file and THEN do a force install. Wow, that was long (i usually don't elaborate very well). I hope that you will be able to help someone with this (your better at this than me). Good Night>>>
Well, that's pretty much all I have. I hope something I've written here will help you, if not then I'm sorry and I hope someone else will have something better to suggest.
Oh, and if you are still reading this -- I just tried to click on the link and it won't work tonight. I have already read on this board that MTS2 is down today/tonight. I really think this link may help you, so please try it again tomorrow as I'm sure that MTS2 will not be down for long. (Well, hopefully they won't, lol!)