It is not the entire cake he wants but one serving. So place the cake on a counter and get one serving.
Sorry to bother you again, but it seems that this is not the solution to the problem on the Italian AHQ. I already asked them to move the Mods folder to the desktop, delete the localthumbcache file and repair the game via Origin, but it didn't work... What can I do now to help them ?
Mods can cause problems in the game so it was good that you told them to test the game without any mods installed. The errand works as I explained with one slice of the cake in the inventory (there is another errand involving cheese where it is also one slice). If the OP tested the game without any Mods and with one slice of the cake in the sims inventory then it should work.
