ERROR Could not complete your request because Assertion in /Volumes/Development...

[doaudio]

When trying to open this OMF or importing the session data, I keep getting this error:

Could not complete your request because Assertion in "/Volumes/Development/151228/ProTools/App/MacBuild/../PtSess/PtAAF/PtSess_Iop.cpp", line 249.

I've looked around on forums and can't seem to find a solution; I've tried changing playback engines, and other OMF's work perfectly fine.
While the OMF .txt shows no errors during export, we have been having problems exporting an OMF for this session all day, so could this be an error on the editor's end or is there something I am doing wrong?

Please help!

(Running PT 11.3.1 on Macbook Pro 2010 15inch 8GB RAM 500GB HD Yosemite OS X, MBOX 2 Pro Interface)