Advice from Ryan Gordon, who created the Linux version...
This extremely unhelpful error usually means that there's a system library that couldn't be found by the dynamic loader (although it makes it look like it couldn't find the app itself).
The installer only links against three things:
libdl.so.2, libm.so.6, and libc.so.6...all of which are part of glibc, and your system just wouldn't boot without them.
My guess would be that you're on a 64-bit system and doesn't have 32-bit libraries installed...the game itself can be 64-bit, but the installer is always 32.
If you're on Ubuntu or Debian, you can try running "apt-get install ia32-libs"
If you gets desperate, the installer is just a self-extracting zip, so you could do:
mkdir cogs
cd cogs
unzip ../cogs-installer-build4
cd data
./Cogs
...and it'll run the 64-bit version of the game.