I am making a map in which the player(s) attacks a base protected by a random private security forces, i.e. monster_barneys and _otis. Now, I realized that having a map where the enemy npcs only have pistols would be a little dull (excluding puzzels and level design of course) so I wanted to give the Barney and Otis models shotguns to spice up the combat a little. However, when I tried to give the barney model a shotgun (circa op4) and its related animations, and tried to recompile it, I got an error that states:
illegal parent bone replacement in model 'dc_soldier_shotgun_reference' 
'Bip01 R Hand' has 'Bip01 R Forearm', previously was "Bip01 R Arm2'
So I tried to use the original Half Life grunts shotgun instead. However, when I tried to decompile it in Milkshape, nothing happened. Nothing. Milkshape did not crash, or give me an error, it just didn't do anything. In fact, most models I try decompile won't do anything, while others, like the Otis model only decompile partially, leaving out many animation reference files. I have no how to fix this problem, help!