oracle8i database

I am getting error from clients ora - 12500 and on server mprotect error fatal and it is showing the file in this directory
$ORACLE_HOME/lib/libjox8.so. Resource on available
Even I tried to reload the oracle8i but I couldn't rectify it.

O.S is := Sun Solaris8(pentium III,256 mb ram & 20 gb hdd)
Oracle database is := oracle 8.1.5
clients are 40 and it is development database

Please get me the solution it is urgent.

TNS-12500 TNS:listener failed to start a dedicated server process

Cause: The process of starting up a dedicated server process failed. The executable could not be found or the environment may be set up incorrectly.

Action: Turn on tracing at the ADMIN level and re-execute the operation. Verify that the Oracle Server executable is present and has execute permissions enabled. Ensure that the Oracle environment is specified correctly in LISTENER.ORA. The Oracle Protocol Adapter that is being called may not be installed on the local hard drive. Check that the correct Protocol Adapter are successfully linked. If the error persists, contact Oracle Customer Support.



also may be your server is running low in resources, 256 mb is not a lot really