I have been at this LITERALLY for several hours. I have tried SEVERAL different tutorials. I've done them 100% correct every single time, the resource.cfg file, the nointro file, and the nobuildsparkles file that is required in every single tutorial i've tried ALL have the black box with "EXEC" written in green on the top left corner. I'm assuming that's why I get them to work, meaning I cannot get ANY CC SKINS installed in my game. Please help. This has become such a headache.

Can you show us a screenshot of your mods folder with the files inside? Also, the contents of your resource.cfg file.

The icon that displays for the package file type is irrelevant (assuming that's what you mean by the black box with exec on it), that just shows that Windows doesn't know what to do with a package file. But the game does.

Absolutely!

I guess if the icons don't matter, then I don't know why the mods won't work, and I cannot for the life of me get a skin to instal into the game :/

Are the instructions the same for a mac as PC?

They are. The OP has some unusual file associations there, though as simsample said that makes no difference at all to the game. They are still TS3 package files (or not) based on what the file is, not how the operating system (OS X Finder) sees them. Same as on Windows.

But skins can be tricky. Assuming they are package based files as well and not sims3packs, it's crucial to delete the five cache files in the top level of the TS3 user game folder to get them recognized. And with default replacement skins, even then it can take a game session or so before they kick in. Again, same as on Windows (sometimes).

If what the OP is saying, there is some inconsistency there, is that the script mods won't work either then two things.
-- Be sure to delete the scriptCache.package file on the top level before starting up, this is one of the five mentioned above.
-- Where is this Mods folder exactly? The Finder windows don't show the directory that it's in.

@Zim Change the view options so that we can see the file path as @igazor mentions.

Also, open your resource.cfg and show a screenshot so that we can see what's in there.

As a former mac user who played the sims, the only thing that worked for me was this installer: http://www.modthesims.info/download.php?t=349349

I guess the reason why is that the sims version for mac doesn't have the d3d9.dll by itself yet thus, the mods don't work. So this installer should do the job! Do make sure you read the description, it has some good information on what to do before installing it!

Let me know if that works

Moved to help

One more note (I really shouldn’t reply on things before my morning coffee :P) is that the exec files are normal don’t worry about the black boxes. There is a chance that your package files will look that way too but that’s totally normal!

I can't get a reachable page out of that link. But this sounds like an issue that would have been present on the Mac side before Patch 1.12 and Ambitions back in late 2010, when mods had to be inserted into a folder deep in Transgaming (the "Old" way) rather than in the user's Documents folder (the "New" way). It really shouldn't have been necessary after that point, if it's the one I'm thinking of.