The pins aren’t assigned properly in PCB view. You have circles in copper layer that aren’t assigned, or should be in silkscreen if they aren’t contacts.
Assuming that it uses headers to fit on a PCB, there is no top copper layer so it won’t work on 2 layer boards.
At 11:00 on this video
Do you have a datasheet, because the pins aren’t on a 100mil spacing.
Something weird with the silkscreen in Gerber export. Export to Gerber and view each layer one at a time on Gerbv
http://gerbv.sourceforge.net
When you assign pins in SCH view use the N,S,E,W selection after you select the graphic. You want connects to connect on pin ends not the middle.
Other than that, that’s a pretty sweet BB drawing.