Their Navy is almost all corvette and patrol type craft, few Destroyers and no capital ships. Their sub fleet is mostly diesel electric and pose a minimal threat also. We always have SSNs in the area, and what the air arm didn't send to the bottom, they would. Most of their ships are a minmal threat in any case. If you're talking 800 ships like Soviet Udaloy or Sovrymenny DDGs or Kresta or Kara CGs or similar capability ships, that's one thing, but they're all much smaller, lower speed, much less armament, and few have any real "blue water" capability.
Their tanks are old Soviet tanks, barely modified since the 80s, and it wouldn't take long for them to lose 2,000. I would't give their armored force more than a couple weeks, and the 2,000 they do have are at best T-65s and T-72s, totally obsolete by today's standards. The artillery would not last long either. Sure it would devestate Seoul and many facilities in range from the border, but air strikes would take many of those out in short time, and most of them their locations are known.
Their Air Force would not last long for obvious reasons. It's mostly made up of old MiGs and SU type attack planes. Maybe some SU-27s, but their pilots are not as good as ours. Their Air Force would last about as long as their navy if they really tried to engage for a long period of time.
Their army is a big threat, but with massive bombing, and other close air support, it doesn't take long to eliminate a million man army now a days even with just conventional weapons. We've killed over 100,000 terrorists in Iraq the past three years (that number is from central command in Baghdad, not official, but the number they use to keep track) and that's fighting an enemy that doesn't mass together in traditonal unit formations like North Korea would.
Their chem and bio weapons are a huge threat, but if they use them, our nukes are on the table, and they know that. Il can't unite the north if his whole nation is glowing in the dark, and I believe that if he launched a chemical or bioligical attack against the South, we would have no alternative but to respond likewise or with nukes. Either way, it would destroy almost all of that huge army of his. And it can't be ignored that many of the North Korean army is not interrested in the facist power hungry plans of their "leader". After 50 years of living in hell under him and his father, they hate him and it's unlikely that those millions of North Korean troops would fight to the death like their grand father's did in the 50s. They have quite a different mindset.
And it's not like the South hasn't been preparing also. They have some hellacious defenses lined up along the border opposing the North. And our soldiers and Marines are d**n good. It's not like we've been sitting around whistling dixie the past 50 years. They have a big army, but most of it's equipment is obsolescent or obsolete, and they don't even have the numerical superiority like the Soviets did in Europe. And while their army is huge, is would take Il 17 years to grow replacements. And he wouldn't last that long. Our equipment is better, and we have the space to deploy much of it out of range of a North Korean first strike, which he can't do because of the relative small size of his country. His navy is out manned and out gunned by ours, same with his air force. And using chem and bio weapons, or nukes against us would result in his total destruction. The world would not tolerate that and we would have to respond by wiping him out completely. A couple tactical nukes right in the middle of his massed troops, far enough that our troops would be safe, would eliminate many of the North's troops if Il pushed us to that. But that won't happen. He wouldn't use chem or bio or nuke weapons. MAD is at least one thing that would work on him that wouldn't with the islamic terrorists. He can't take over the south, if the north is obliterated, and that's what would happen if he used nukes or chem or bio weapons. We'd do to his country what we did to it in the 50s before the Chinese came in. The whole country was ours exceptfor the tiniest of areas and the North was defeated. That's just my take on it. And those reports are always made to sound as ominous as possible, though it is a very serious situation and would make Iraq look easy. The defenses in the South are VERY good, and I'd much rather fight a defensive war than an offensive war. It's always easier to defend your own back yard then go into someone elses and try to take it from them. So defending gives us an extra advantage if he ever attacked. But God willing he won't and the government will some day collapse under it's economic weight. God willing.
They can wreak so much havoc even though they have obsolete items. I would say most of the things in that report is mostly accurate.