Error upon opening a file in AutoCAD

Hello,

I recently edited a file (built in 2 new scenarios along with necessary alternatives) in the stand alone platform and ran the new scenarios with out any issues. However, when I went to open this edited file with AutoCAD I received the following error:  "Attempted to read or write protected memory. This is often an indication that other memory is corrupt." Originally we thought this was bad RAM, but new RAM cards proved that to be incorrect. If I click OK on the message several times I can get past it, but the CAD functions no longer work (such as layer manager)...if I attempt to execute a CAD command, the program simply crashes. I do not think the error is with AutoCAD, though, since only this particular file is giving me issues, and it only occurs when I create a specific scenario. To get around this issue, I have done all of my editing withing AutoCAD. This worked, but now when I run this particular scenario I get an error that tells me to look at the Validation dialogue. However, when I run the validation it simply says everything is fine. 

 Has anybody run into this sort of thing before? If not, I can send the file with directions to create the issue if necessary. 

 Thank you,

Jeff