It doesn't matter what icon appears or what "type" your operating system thinks the files are, that's just the auto-open preference for when you double-click on a file. If you don't have a package editing program installed such as
S3PE or NRaas Packer, and you have no intention of creating or editing package files on your own, then there is no point in double-clicking on .package files anyway. The game knows what to do with them no matter what they look like. Or at least it does when things are working correctly.
Things that are important are, the files must be .package (not zip, rar, or something else) which you can see if you have file extensions showing, they must be intended for TS3 (no content from other games and no .sims3pack files), and your Mods\Packages folder with the required Resource.cfg file must be arranged exactly as illustrated here, plus or minus some variations around the edges in different operating systems. You should also clear (delete) your game folder's cache files whenever the contents of Mods\Packages changes in any way.
http://modthesims.info/wiki.php?tit...Setup_and_Files
Does that help at all?