I have AI CS6 and when it gives me an error , it’s @100% when a font is scaled to 0. Illustrator can’t handle font bellow 0.1(pt). This happens when the export scaling is very tiny. I troubleshoot this case by editing the ai file (with np++).
https://discourse.mcneel.com/t/illustrator-export-font-size-error/37056?u=piem