VPK's no longer working in addons folder ?
Am I the only one having this problem rightnow ?
Nope, I have same problem, no .vpk:s working in addons OR same way as posts above said how to fix that.
I asked cher & eric for a quote on this on email about this...
Path: steamapps/common/portal 2/myportal2mods
That worked
That's what valve did with the dlc.
So just move your addons folder up one folder
Valve made the dlc as an addon, but instead, they just put the folder inside the portal 2 folder instead of portal2 addons folder
I noticed that their content was inside its' own little folder and wondered why they did it this way. Spongy, you might want to explain a little better where you created the vpks and which folder you place the vpks to work.
Having the same issue with my Portal maps..... tried everything!
Wondering whether the dlc pack that came in this week has something to do with it? using the map command to start a .vpk file seems to cause the game to search the map folder for a .bsp file and has no way of unpacking the .vpk file.
Tried using the DLC folders, adding an addoninfo inside, making a pack089 and dir2... nothing.
edit
I made a portal2_dlc2 folder along the first, extracted the files inside and they worked. Putting the vpk in the addons of the same folder wouldn't work. By the way, it does a weird loading thing when you run it the first time... maybe it's downloading the next DLC from Valve's server. 
I tried the portal2_dlc2 trick. I got a loading screen before the menu. When the bar had filled up, it turned orange and sat there doing nothing with the wheel spinning. SOme files were changed, though - I used an empty portal2_dlc2 folder and an empty maps folder was created, with an empty soundcache folder. It is still doing it as I post.
Someone pointed me to a very useful alternative:
http://www.se51.net/2011/09/15/how-to-m ... tal-2-mod/