Download the tclwebtest source, unpack it, and put it an appropriate place. (tclwebtest 1.0 will be required for auto-tests in OpenACS 5.1. When it exists, the cvs command here will be replaced with http://prdownloads.sourceforge.net/tclwebtest/tclwebtest-0.3.tar.gz?download.) As root:

cd /var/tmp
cvs -z3 -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/tclwebtest co tclwebtest
#wget http://umn.dl.sourceforge.net/sourceforge/tclwebtest/tclwebtest-1.0.tar.gz
#tar xvzf tclwebtest-1-0.tar.gz
mv tclwebtest-0.3 /usr/local/
ln -s /usr/local/tclwebtest-0.3 /usr/local/tclwebtest
ln -s /usr/local/tclwebtest/tclwebtest /usr/local/bin