garageband quits on exporting to itunes

I get a very, very long error message that is way beyond my comprehension.

I have been trying to record LP's into garageband and transfer into iTunes. From any tutorial i've seen i seem to be doing it correctly.

The only thing that could possibly be wrong is that my iTunes files are a bit of mess so perhaps the pathway into iTunes isn't reading correctly (so i have an 'iTunes original' file that i created and where my music is stored, but the garageband downloads are going into a separate 'iTunes' folder, if you see what i mean), Having said that, when i do locate the garageband file, it is saved as .band rather than .aac or .m4p or whatever it should be, so i feel as though it is more of a problem with the conversion as opposed to where files are stored