It's hard to give exact rep steps for this one, but the problem happens in a schematic/board I have been working on (originally imported from Eagle). I have a couple of screw type 5mm x 2 terminals in the schematic (SCREWTERMINAL-5MM-2) that seem to be causing a problem, though I can't see where the issue is in the schematic.
When importing changes, I get:
Package Error!
Pre: PROBE RELAY
PROBE and RELAY being the labels for the screw terminals. Help!