I was installing a binary Linux application on Ubuntu 9.10 x86_64. The app shipped with an old version of gzip (1.2.4), that was compiled for a much older kernel:

$ file gzip 
gzip: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.0.0, stripped

I wasn't able to execute this program. If I tried, this happened:

$ ./gzip
-bash: ./gzip: No such file or directory

ldd was similarly unhappy with this binary:

$ ldd gzip
        not a dynamic executable

This isn't a showstopper for me, since my installation has a working version of gzip I can use. But I'm curious: What's the most likely source of this problem? A corrupted file? Or a binary incompatibility due to being built for a much older {kernel,libc,...}?