I've seen a couple of reports of this, and it seems to be a problem with After Effects failing to establish communication with the component that it uses to communicate with Apple's 32-bit QuickTime system (Adobe QT32 Server).
Typically, when this sort of problem occurs, it's because of an overly aggressive firewall or similar software blocking communication over TCP.
There's more detail about that here:
troubleshooting QuickTime errors with After Effects CS5, CS5.5, CS6, and CC