After reading http://www.soccergaming.com/forums/a.../t-171344.html
regarding how to edit details in the player database I was able to extract all the files in the data0.big file by using Dragon Unpacker. I put all those files into C:Program Files>FIFA12>Game>data>db.
I was able to edit the player database with FIFA12DBM so no problem with that.
So I then deleted the data0.bh and data0.big files (I kept a back up of them so no problems on that one) and then used the iRegenerator 1.6 (I chose the one to take care of the files in the edited folders)
And then I clicked FIFA 12 and it doesn't start anymore. I only got it back up after putting the backups in place to the original folder where I deleted the bh and big files.
So how can I fix this issue?