I called HP directly about this issue, and these were my findings: I didn’t want to sign up on HP’s lame forums to post the solution either, so here goes.
Our print job hung on our Laserjet 4350tn. My findings were that it defaulted to the USB port DOT4_001. When running parallel it needs to be LPT1. It was a large check run in the queue, and it hoses up our Accounting system if it cannot print. I had switched it to LPT1 before calling HP, and it printed fine. HP verified my findings.
They said if it keeps defaulting to the USB port to reinstall the drivers.