You need an editor like this (https://github.com/dnSpy/dnSpy/releases) to open those type of files and maybe he edited the team form from 2020 to 2030 because in the team section where the error appears, I think that's it.
You'll go to C:\Program Files (x86)\Games\FIFA 15\dlc\dlc_FootballCompEng\dlc\FootballCompEng\data
and find a file named cmsettings.ini open it and you search for CALSTART_YEAR and change the year for ever you want. You said you import files from another patch are you sure that the patch is...