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Hi,

You need to update your AutoCAD 2013 - install Service Pack 2:
http://knowledge.autodesk.com/support/autocad-for-mac/downloads/caas/downloads/content/autocad-2013-...

and then Service Pack 3:
http://knowledge.autodesk.com/support/autocad-for-mac/downloads/caas/downloads/content/autocad-2013-...

BTW, which OS X do you have on your Mac?
If it is Mavericks (10.9.X), than you can proceed with updates without any issues, if your OS X is Yosemite, than you will have troubles with SP2 installation. Than post here, I'll try to help you.

Maxim