Hi, I have a drawing that has started exhibiting very odd behavior.  When I delete some lines in model space, DS crashes with the message seen in the attached image.  Some lines do not trigger this effect, others do.  Lines that do and don't are essentially identical, as both were drawn at the same time, using the standard "l" command, are on the same layer, etc.  

I have tried saving it with a different name, but that doesn't fix the issue.

I am running the current version on osx mountain lion.

Thank you in advance for any help on this issue!