Sorry dude. I don't know what is causing this. But I would start by mixing down with no effects and making sure the volume doesn't clip to check if it's effects related. You might also want to try "bounce selection" that way you can see if it's something on one track hanging it up and you'll know which track and can go from there. If nothing hangs up, you can trying mixing down the bounced tracks and see if it still freezes at 1:39. Sorry I'm not of more help. Good luck.