Hi, I would recomend to copy you system datat befor trying this.
You can start the game then select "NO" every time the game asks you if you want to save, DON`T select a memory device. Then download the data packs, again select "NO" if he asks you if you want to save new system data. After downloading and installing the data packs quit to dashboard and start the game again, your version and data packs now should be on the same level while using your sytem data.
If that doesn`t help:
You can delete data packs in the system settings of your Xbox360.
Problem will be you need to find and install the right Title update version for your system data. You can do it like this:
Download the the title update from here
http://marketplace.jqe360.com/main.p...tails&tupage=2
For my german version I downloaded the file with the MediaID: 5F36AD2D Title: PES 2014WE 2014 TU 7 if that doesn`t work try one with another MediaID.
Then I connected my 360 harddrive to the PC via the transfer cable
http://www.amazon.com/Xbox-360-Data-...transfer+cable
Next using the freeware "Horizon" under Tools -> Device Explorer -> Title Updates deleted the PES2014 update. Then via "Inject new file" injected the downloaded title update.
And thats it. If you don`t have the transfer cable I guess a Flash drive might also do. Hope that helped let me now if it works.