Hi Bryan,
Other users have reported similar problems, and filed bugs (please feel free to do the same: http://adobe.com/go/wish). Here is a relevant thread:
https://forums.adobe.com/thread/1640114
The common factors appear to be using After Effects CC 2014 on Mac OS X 10.10. Some users have solved the problem by reinstalling After Effects, others have removed a plugin, or even gone as far as reinstalling Mac OS X.
We have investigated this problem but have not been able to reproduce the bad behavior. Any information you could provide on what happens before you encounter the inability to import would be helpful.
One specific request: the next time you encounter the problem, don't do anything else in After Effects. Open Activity Monitor, choose the After Effects process, then click the Sample Process button. Save the file and please email to me, myLastName -at- Adobe dot com. If you could also share the project file, I'd appreciate it (in it's last saved state before the problem occurs).