I'm not entirely sure where to post this, because I use PeTI for my puzzle making, but traced down the problem to vbsp. Because vbsp is not only related to the Puzzle Maker, I figured I'd post this here. The problem I'm having is this. I recently wanted to try a new concept that I came up with for a test chamber. Designed a test chamber, tried to build. Crash. The dev console pointed me to vbsp, so I looked into the /bin folder for Portal 2 and tried to run vbsp_linux through a terminal. At first, it turned out that the libraries weren't in the right place, so I fixed that. Hoping this would fix it, I tried running vbsp-linux again.
By the way, this is the terminal input:

usr@wowsuchpc:~/.local/share/Steam/SteamApps/common/Portal 2/bin$ ./vbsp_linux -entity_limit 1750 -game ../portal2 ../sdk_content/maps/blabla.vmf

Had my hopes up for a second as the program didn't output much for half a second, then it crashed. This is the output I got:

Valve Software - vbsp.exe (Jun  4 2014)
1 threads
Could not start the empty shader (shaderapiempty)!

...So I looked into the folder vbsp_linux is in. It contains 2 files with that name, one being a .dll and the other being a .so file. I tried renaming the shaderapiempty.so to just 'shaderapiempty'. It did have effect, though not what I hoped. Instead of a "could not start shader" error, I got "segmentation fault". Reverted the namechange. Removing the .dll extension didn't do a thing.
So now I'm stuck. I really hope you guys can shed some light on this problem so I can at least get vbsp working.

Many thanks in advance,

aeTIos

I would report this to Valve since they are doing the whole linux beta stuff.. The "Could not start the empty shader (shaderapiempty)!" message is typical, we see it in Windows.

Ah, okay. I'll do that, then, especially because on another forum I also got told to report this to valve.
I'll get back to you if I get it fixed.