Gino,
Regardless of the platform you are using,
you should have an ORACLE_HOME environment variable defined which points to the home directory of the Oracle installation. The "bin" directory -- mentioned earlier in this discussion -- is a subdirectory of ORACLE_HOME, so the full path of the
SQL*Loader executable is:
You can find more information about the ORACLE_HOME variable in the "Oracle Installation Guide" for your platform.
Good Luck,
Avi.