Display/plot issue

I detached some photo backs (ecw files?) from a reference in the plan view in a Transmission P&P drawing, but now the elements in that reference don't plot or display in preview. Also, a line string in a completely different reference (which i didn't modify) in the plan view plots in a different line-type.

 Apparently, my guess thus far is a setting? Other computers in my area show it correctly while one only shows the line string correctly from the 2nd reference but doesn't show the original stuff from the first reference.