ok, chances are you are missing another mod needed for the Panther to work - have you made sure you've checked if it requires any other mod to work?
i'd have a look myself, just can't stay at my pc right now. i'll check later when i get a chance, meanwhile better you double-check on that.
oh, for the logfile info, read the relevant sticky in this section, 3rd or 4th from the top.

edit: i see that plane requires the catapult mod. there is also a fix to d/l in that same first post for the Panther, in case you don't have the catapult mod. did you go through that?