Whenever I try to start the game from console with ./start.sh I get:
support/gog_com.shlib: Line 211: ./PillarsOfEternity: no permission
(translated from german)

My system is (K)ubuntu 14.10 64bit
Kernel-Version 3.16.0-34

AMD Phenom II X4 945
4 GB RAM

BTW, the code block around line 211 of gog_com.shlib says:
if [ "$arch" == "x86_64" ]
then
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$lib_path64"
cd "${bin_path64}"
./"${bin_64}" <- 211

Have you tried running the game directly from the 'PillarsOfEternity' binary, found in the 'game' directory (next to the 'start.sh' script)?

Did you install the game in a "non-standard" filesystem, like NTFS ?

I aksed because last time someone in the GOG forums had "permission denied" when running it was due to that.

If it's not one of the above problems, check of the binary is executable. "chmod a+x PillarsOfEternity" in the game directory and run it directly.

If it still doesn't work run ldd on the binary "ldd PillarsOfEternity". If there is a missing library (libbla.so.1 => Not found) it may cause the problem.

If there is one missing and you don't know which package it belong to, you can install "apt-file", then run "apt-file update". After that "apt-file search libBlah" will print the corresponding package name.

Thx, that was it. Should've known there are binary files also missing executable rights, doh.