I'm running into this problem but the situtation is a little different than most of the solutions I've found.

 

I recently switched from a VPS to a dedicated server.  I moved about 20 sites that all have fully funcitoning k2 galleries.  After the move to the new server I'm getting this error message:



UNKNOWNARCHIVETYPE
Gallery upload error: Cannot extract archive!

 

All other aspects of my sites appear to be functioning correctly, including loading k2 item image and also loading joomla install packages (zips). 

 

The sidebar says my upload limit is set as 256Mb and my permissions are 0755 on the /media/k2 sub folders.

 

Since it is effecting all of my sites, and they used to work, I suspect a setting on the server but don't know where to look.  I have also seen this issue on this forum from some other folks that moved their VM, but no answers.

 

Any help out there?

 

Thanks