On Solaris, I noticed setting LD_LIBRARY_PATH in a ruby script is not effective. You must set LD_LIBRARY_PATH in your crontab:
00 12 * * *
/usr/bin/env LD_LIBRARY_PATH=/opt/oracle/lib /path/to/script.rb
or set LD_RUN_PATH (or ld -R option) at the compile time [using mkmf for example].
It only took 6 months to get an answer out of him or Mr. Neumann, but I *finally* got one!