Operation Guillotine Problem

Hi guys was wondering if anyone had experienced this and had any luck figuring out my problem.
Basically if I try and pick up a new weapon at any point during the mission it goes through the motions of picking up the weapon but then I have no gun and I cant do anything but run around.
Once I get I killed it then goes to the endless black screen with the only way of getting of the screen to quit the game. I'm currently stuck on this mission and haven't been able to progress yet because I always end up running out of ammo unfortunately and i can't pick up a gun, hopefully this is only a glitch within this mission. This was happening before and after patch 1.07?? (i think that's the one)
Any help will be appreciated.