MacOS – Grey Volume bar – coreaudiod – Job failed to exec(3) for weird reason: 2

The first thing to check is to see if iTunes has marked those specific songs to end early. Next, try re-encoding the song at a lower or different bitrate and syncing it to the device. Often a glitch in the file can cause iPods to skip to the next song, but the same binary file plays through on macs with better code for handling errors. Lastly, it could be error creeping into the filesystem structure on the iPod. Once you're sure you've backed up everything from the iPod, you can enter disk mode and use Disk Utility (on the mac - on Windows there are lots of disk formatting tools) to zero the drive. That will test the actual hard drive for errors and spare out any bad blocks.

Feel free to edit this or comment if you find none of these helps narrow down the cause.

I found this problem too! Turn off parental control and it works fine. Interesting as I have two Mac Pros and one with PCs on does allow MC to work. The other with the PCs on and it does not. I suppose best answer is to turn off Parental Controls for an separate account just for users whom use AVID.