So, I just got back into Far Cry 2 and decided I want to beat it. I got pretty far in, but when I get done with the 23rd mission (SPOILER: where you blow up the water pipes and flood the canyon), I would go back to UFLL HQ, the guard would take away my guns and let me in. But, there's no one inside, the door to the guy's office is closed, and I'm unable to get a mission there. The guard outside the APR building won't even let me inside... What do I do? Is it some sort of glitch (which I hope to god it's not, I'm like 73% into the game)?

I don't play this but a walkthrough may help you.

Here's one that should help (http://wikicheats.gametrailers.com/Far_Cry_2_-_PC_PS3_XB360/Walkthrough)

@odinn7 I've been looking at walkthroughs, but it's hard finding the part that I'm at.

It only takes a little bit of reading. I don't play the game but I scrolled down to the Pipeline Crossing section based on only what you said and it looks like the section you need.

Yea, it's not the pipeline section, I thought it was, but that was the last main mission I remember doing. I've been watching a walkthrough starting on the pipeline mission, and I remember doing the missions the guy is doing afterwards

Ok well, good luck with it and maybe someone here that knows the game will come along.