sounds like the telnet daemon might not be running, or possibly a firewall issue on your linux box.
from the command line type
ps -A |grep telnetd
if you get a line returned with telnetd in it then the process is running, otherwise it isn't.
to get it to run,
/sbin/chkconfig telnetd on
/sbin/service telnetd start
first line tells it to start at bootup, second tells it to start now.