AOLserver 4.5 is available in Ubuntu. You can install it with apt-get install aolserver4 aolserver4-nscache aolserver4-nspostgres aolserver4-nssha1
You can use the standard Tcl installed with Ubuntu also.
Here is the rest of the debian packages install doc
https://openacs.org/xowiki/openacs-system-install-debian
which should eventually be available directly from the ubuntu repository.
