The ifup-ipx script is used to bind IPX to a NIC at startup.  The script
has two small bugs in it that cause it to fail.  First it looks to /usr/bin
for the ipx_interface command which is located under /sbin in RedHat 6.1.
Second there is a small paramater passing error on the ipx_interface
command line.  The $primary should be the 2nd parameter on the command
line, it is listed as the third in the script that shipped with RedHat.

Here is a copy of the "modified" working script:

/etc/sysconfig/network-scripts/ifup-ipx

#!/bin/bash
# configures IPX on $1 if appropriate

PATH=/sbin:/usr/sbin:/bin:/usr/bin

if [ "$1" = "" ]; then
	echo "usage: $0 <net-device>"
	exit 1
fi

if [ ! -x /sbin/ipx_interface ] ; then
	# cannot configure IPX with non-existant utilities
	exit 0
fi

. /etc/sysconfig/network

case $IPX in yes|true) ;; *) exit 0 ;; esac

cd /etc/sysconfig/network-scripts
. network-functions

CONFIG=$1
[ -f "$CONFIG" ] || CONFIG=ifcfg-$CONFIG
source_config

for frametype in 802.2 802.3 ETHERII SNAP ; do
    # Yes, this kind of evaluation is really necessary to do this.
    # Welcome to shell programming...  No, we were not smoking some
    # particularly good floppies while we wrote this.  :-)
    framename=$(echo $frametype | sed 's/\./_/')
    case $(eval echo $(echo \$`echo IPXACTIVE_$framename`)) in
	yes|true)
		case $(eval echo $(echo \$`echo IPXPRIMARY_$framename`)) in
		    yes|true) primary=-p ;;
		    *) primary= ;;
		esac
		/sbin/ipx_interface add $primary $1 $frametype \
		  $(eval echo $(echo \$`echo IPXNETNUM_$framename`))
		;;
    esac
done

exit 0