The function findInterfaceInfo() in net-setup.sh picks up the string, fails to sanitize it and blindly sets the MANU variable accordingly.
The (dynamic) gtkdialog3 script fails miserably (as '<' is used as its tag deliniter) and network-wizard exits, unable to tell the user what happened.
The function findInterfaceInfo() in net-setup.sh should filter out '<', '>' and other gtkdialog3's special characters for the PROC/MANU/INFO strings.
Add the following before findInterfaceInfo() returns:
# if PROD / MANU / INFO contain the < or > characters, the produced gtkdialog3
# script will fail; so remove these dangerous characters
PROD=$(echo "$PROD"|tr -d '<>')
MANU=$(echo "$MANU"|tr -d '<>')
INFO=$(echo "$INFO"|tr -d '<>')