Hello,
I'm very new to the Sims and just started playing Sims 3 about a month ago, never played any Sims before (75% off on steam, just couldn't pass the opportunity!)
I've been pleasantly surprised with the game and growing fond of it every day. The possibilities to improve on the base game seem to be limitless. I've been trying different mods here and there and been very impressed. The creativity of people is also amazing, I've been downloading custom content from TSR and the skill of those people is pretty awesome.
I have some experience modding other games (Total war series), mainly scripting. I've never been a skilled graphics guy, there are much more skilled people for that. So I just use their creations and incorporate them in my personal mods.

Anyway, after giving you a brief "bio", let me get into the substance.
I am trying to learn about modding the Sims and the main tool seems to be S3PE.
So, I downloaded it and read some tutorials. I then tried to open the game's 'gameplay.package' [G:\Steam\SteamApps\common\The Sims 3\Game\Bin] to check it out. However, it appears I'm having some issues. When I try to open it I get this:




So, any idea what's going on?
Is there another utility that allows to open .package files to be edited?

Thank you for your help.


PC Specs:
OS: Windows 10 (net framework 4 or higher is included in windows 10)
i7-3770 @ 3.4 GHz
RAM: 16 GB
MoBo: ASUS P8Z77-M Pro
GPU: EVGA GTX 970
PSU: Corsair CX750M
SSD 1: Samsung 840 Pro 256 GB
SSD 2: Samsung 850 EVO 500 GB
Case: Fractal Design ARC Mini R2

I wonder if this has something to do with the Steam version of the game. It has a different gameversion and install location to the Origin versions.

By the way,
The pic I posted was not the right one. It seems I was actually able to open the gameplay.package file.
I was having problems CC .package files when I tried to merge them...I'll post the error shortly.