First video:

Yes, they did know about the terrorists before they struck on 9/11. But they also knew about a few other terrorists worldwide, and couldn't act on those specific ones, because they didn't know that those terrorists were planning anything worse than any other terrorists.
The classified information ban given to the colonel is pretty standard. Once he's revealed information of a classified nature to a person, regardless of what the classified information was, he cannot be trusted further. It's not a morality question, it's just a logistics question. Somebody who's told something in the past for whatever reason, likely isn't as prone to keeping things quiet in the future with other sensitive information.
Now, about the documents they mailed him: That was a classic screwup, and very embarrassing for his agency. Can't really defend them there.

Second and third video aren't working for me, could you find a new link?

Fourth video was rather interesting, but had the unmistakeable stench of the average 'conspiracy theory' videos. The sort that give just enough information on an odd case to make it seem incredibly out there, far more bizarre than it actually is. I definitely get the feeling that the conspiracy theorists are leaving out some bits of information to make the video seem more incriminating and bizarre than it actually is.

Fifth video: Al-Quaeda and Iraq did have links, just not in the 2000-2001 time period. They'd worked together in the past, but they weren't working together on the 9/11 attacks. The Bush administration is pretty inept, at leat in it's handling of the 9/11 issue. We can all agree to that. Now, did Iraq work with Al Quaeda on 9/11? Probably not. But was Iraq a terrorrist sponsor? Hell yes. Same with Iran, but Iran's trying to clean up it's act now to look better for the UN. Do I advocate the war in Iraq? No, at least, not for the reasons Bush supposedly started it. But I think our role there is crucial in restoring peace to a war-torn area. There's no doubt Saddam is evil. He had thousands of his people gassed and executed, then buried in mass graves. We're still uncovering those graves today, but they've been relegated to the third and fourth page of the newspapers, pushing more anti-Bush stories to the front page.
And let's not forget that we FIRST went to war in Afghanistan, not Iraq. Afghanistan was were Osama Bin Laden was located, and that's who initiated the attacks on the USA. AFTER Afghanistan, we moved to Iraq. Yeah, the president fucked up his reasoning there. But there's no doubt that Iraq harbored terrorists in the past, and would continue to do so in the future. They had chemical weapons, we know because they USED them on their own citizens a few years ago. Nukes, I don't think they had. They were most certainly TRYING to get them, but they weren't getting far.

Sixth Video: Weather control is a thoroughly debunked idea. Remember this thread? Weather Control And the guy's polymer idea wouldn't work that well. Those polymers have been known about for years, but they won't do what he wants them to. They're actually used in diapers, too. But they won't work there, either. At least not as well as they should. The problem is that such a polymer works well with pure water, but the ocean, and baby piss, aren't pure water. The ocean is salt water, and salt happens to almost perfectly inhibit the reaction. He could pour all he wanted, it just wouldn't work. As for the jet engines: Like they said, yeah, it could likely change the course of a hurricane, but we don't know in which direction. It could cause a lot of problems if it hit another city, and we'd intended to make it miss the coast entirely. That's why they aren't using it to stop hurricanes. And if they wanted to steer hurricanes towards the US, they likely wouldn't use it either. Do you remember any sightings of huge barges carrying huge packs of jet engines? I don't. If they existed, the users couldn't have predicted were it would've ended up. In fact, no matter how hard they tried they couldn't figure out where it would end up. Even if they had amazing future technology. Read up on Chaos Theory. I just posted somewhere else about it, coincidentally. Basically, there's more variables than anybody can keep track of, so you'll never know where it will strike.

Seventh video and all after that aren't working either.