Is there a fix for an NXT reporting "File error!" when running an EV3 program?
I needed to update the firmware. 1.05 was too old. 1.31 works.

Download from:
http://mindstorms.lego.com/en-us/support/files/default.aspx#Firmware

I did need to run the old NXT-G software to download the newer firmware.  I did not try to download the firmware using EV3.