still having problems against VCs

So, I have been having problems playing against my friend who plays VCs. We have played about 20 games and I am 0-20. Its getting to the point where I just dont want to play anymore and my play group is really small so I don't really have that option.  He brutally wrecks me every game without even a sliver of chance so I was wondering if I could get some in depth help.
We tend to play 2500 point games. the biggest threat on the table is this vampire lord on a dragon. It basically does everything and is a 1 man army. It on multiple occasions has wiped nearly every model off the field.
I've tried shooting it with cannons and lead belchers but they just don't do enough damage to it. needing 6s to wound with belchers and often 5s to hit means he takes almost no damage before his awesome saves. with the cannons I hit the dragon or the rider, so it doesn't focus it enough to do enough damage to kill either before he heals it with his casters. 
Another problem is that he beats any of my non-horde formation units in combat. Ironguts are rolling 6 then 6 to wound. (He has a upgrade that makes it so my great weapons don't work). at the very best he holds my best units up for long enough to get charged by his crypt ghouls.
against the rest of his army, I don't have to much of a problem. The Mortis engine eats me alive though.

So I am looking for any help I can get. I am starting to think Ogres weren't the right choice for me 

Cannons, and any other template weapon, hit both the Rider and the Monster. There is no randomization, both are taking the hit.

Mortis Engines are Ironblaster food too.

I am not familer with an item that negates Great weapon strength. I call foul.

I am not familer with an item that negates Great weapon strength. I call foul.

Actually its and item called the nightshoud and what it does is any models in base contact with it lose their strength bonuses.

Ok, but you are still Str4. Is the Vampire T6 for some reason?

As mentioned, cannons hit both the mount and the rider. It should be pretty easy to at least knock the dragon out from under him(it only has a +6 regen save).

Actually, remember that the Night Shroud only works on models in btb. Your 'guts giving Supporting attacks from the 2nd/3rd rank should be merrily pounding the dragon. I would not direct attacks at the Vamp lord, you need 6s to hit that jerk and he should very quickly crumble before your 'guts without his mount.

Also remember that your units are steadfast against the dragon if you have even only three models, because he'll have no ranks to your one rank.

Maybe get a Firebelly to help smack down the Crypt Horrors?

The first thing I'd do is read up on the section for shooting template weapons at characters riding monsters - the cannonball hits them both. With that in mind, double Ironblaster obliterates the Vampire Lord on a Dragon.

Combat shouldn't be much of an issue if you stick to the following matchups - Mournfangs v. Ghouls/Skeletons/Zombies, Ironguts v. Black Knights/Blood Knights/Crypt Horrors/Grave Guard/Vargheists. Given that your army should be more mobile than his, guaranteeing these matchups should be a cinch. Also consider some Maneaters with Sniper to pick off any other characters he brings, as they're likely to be vulnerable.

The only real way for VC to completely trump card us is to throw a Purple sun straight through our biggest unit and characters (assuming you are fielding a star with most chars in it). 

Without Psun they can still be a bitch of an army to deal with.  But not so much that it can't be done.

As everyone already mentioned, remember cannon hitting both rider AND dragon and ONLY models in B2B loses their strenght bonus, not those making supporting attacks.

Also, it might help if you can give his precise build for the lord.  As far as I know the vamp can also only get 1 set of attacks extra with red fury, he can't get any more attacks from the new ones.  That means even with sword of bloodshed, hitting and wounding all his attacks he can't put out more than 14(16?) wounds.

True that is a LOT of wounds, but then he has to hit and wound ALL his attacks and run with bloodshed and I don't think he will have much in the way of defence when running around with a weapon as expensive as that.  Anything hitting back should be able to put some hurt on him.

Please post his list and your own available models/units so we can give indepth advice on your possibilities.

D...

death fist his wizards
 purple sun his units

flaming sword the cannon
cannon the dragon

club things to death with your big clubs

Flaming Poison Pistol Stubborn Maneaters are the cure for most of your problems.  Toss in an Ironblaster or two and the dragon should be dust before it even makes it into close combat.