That\'s strange. This kind of errors usually appear, when You try to execute a file, which has invalid format.
Do the following:
file ./updater.bin
You should see something like this:
updater.bin: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.2.0, dynamically linked (uses shared libs), not stripped
If You can\'t see \"ELF 32-bit LSB executable\" it means, that your files may be corrupt. Redownload and reinstall.
Also: The first slash in the path bothers me (I mean : /planeshift/updater.bin), is that file really in /planeshift folder ?