I think once it downloads the files it should copy the files to your l4d2_beta/addons/workshop folder. (with a unique numbered.vpk with also a jpg for the thumbnail..)

Did it not do this?

it does that, but i cannot see it on the menu to create a server. I had to move a mutation to l4d2/addons for it to work, which kinda beats the purpose other than downloading from steam

Motanum, are you talking about Dedicated Server or Server inside the game? If first, then Chet said "Dedicated servers currently do not work with Left 4 Dead 2 Beta."

I am talking about creating a "local server", so I can host as I play the campaign and other can join me. The issue is the map lists for addon coampaigns (The list yo get to when selecting a campaign>addon campaign) is in blank, so I cannot play any.

Strange, 12/28 Update have fixed this issue for me.

The mission script is what causes a campaign addon to show up in the campaigns list, so since that file was getting corrupted previously, that would cause this problem. If it's still happening even with valid campaign vpk's, I can take a look at it.

In which vpk directory should I see if it is corrupted? So I can check first, I don't want to send you guys in a goose chase.

I was able to upload and then subscribe to my campaign that Motanum was trying to play and then select it via the addons' list and play it no problems.

Motanum why don't you unsubscribe to my campaign then make sure any vpk's in the workshop are removed.(if mine is the only one your currently subed to) Then just in case clear the UGC directory, (Steam\userdata\NUMBER\ugc)

Clear out this directory then once this is all done try resubscribing to my campaign.. Keep in mind other workshop items are stored here so if you can find my addon in the UGC you should be able to clear it out and leave any others...

By the way yes, Motanum, You may have old, corrupted vpk files of this campaign. Perhaps your vpk files weren't updated, when GShock uploaded new version.
I just checked, Downtown Dine works perfectly for me.

Let me try. I thought i hadn't subscribed to it before.

I followed Gshock's instructions. I am going to subscribe now to Downtown Dine

It finished downloading. I cannot see any addon at all. I deleted all manual vpks too, I am still susbcribe to some of thouse though. Is there a verify integrity of workshop item?

No, there is no integrity verification in that case. Open up the VPK in question and look about 3/4 of the way through the file to see if it's all zeros. If it is, it's still the corrupted version.

There is no Downtown Dine vpk. I looked through C:\Program Files (x86)\Steam\steamapps\common\Left 4 Dead 2 Beta\left4dead2_beta\addons\workshop and it is not there. Even though the download library tells me that it downloaded 350 MB of data, which is the size of the campaign, says GSchock.