The Sims 3 Complete trouble installing

I have downloaded The Sims 3 Complete (OS X) and started following the instructions which said i had to download a Sims 3 add on from this site. I did this, i downloaded Sims 3 Showtime. I am now a little stuck, it seems i should install showtime before doing anything with the complete sims 3. However i can't seem to do this, i have created a dmg image with the showtime copied in. I then click on the sims3ep06setup.exe but it says the content cannot be extracted with this program. I have tried two different programs. Can anyone help me through this?

Sorry in advance if it is something really simple, i'm a bit new to this.
Thank you

Hello and welcome!

At this point, I'd recommend you follow these steps:

1. First, delete the .dmg you've created.
2. Open the Showtime file that you've downloaded from here with StuffIt Expander (If you don't have, pleasen download from here) and extract the file on the desktop.
3. Now go to Applications/Utilities/Disk Utility. From the menu above select File/New/Disk Image from Folder.
4. Choose the file you copied over the desktop, name the .dmg and choose where want to put it(I recommend putting it on desktop again)
5. Wait until disk image is done. Then double click to open .dmg. The installiation of Showtime will pop-up.

It should work, but if not please let me know.

I followed your steps but when i open the dmg there are only 3 files there, the instructions, crack folder and installer app. When i click on the installer app in appears on my dock but does nothing and when i click on it, it disappears. When i follow the online instructions ad make my own dmg and copy the files in, i obviously have all the files but the same happens with the installer app, although the instructions say i should click on the Sims3EP06Setup.exe file but this says i can't open it.

Hello,

Are you sure you're using a StuffIt Expander to open rar files? And can you tell me how big the Showtime game file you downloaded? How much GB?

I used an app called the unarchiver to open the rar file, as this is the default and has always worked for me. I no longer have the rar file as once it had been opened i deleted the rar file. The Showtime file is 4.08 GB.

Okay, just create another .dmg with the files you you opened with unarchiver then.

This is what i had done firstly. I dowloaded the rar file from this website. I then opened it with the Unarchiver, which gave a file of 4.08 GB. I used this for the DMG using the way you said and also the way stated in the instructions on this site, but neither way works?