Guys,
IMO, somehow this line is causing the problems:
/usr/bin/sed -i.bak -e 's=/usr/ports=${WRKDIRPREFIX}/usr/ports=' -e
's=/usr/ports/x11-toolkits/tk84=${WRKDIRPREFIX}/usr/ports='
/usr/ports/x11-toolkits/tk84/work/tk8.4.6/unix/tkConfig.sh
Zoltan