Dependencies

Software you need to install first

Apache (probably Apache version 1.3, unless you want to build your own version of Apache 2.0 which doesn't include PCRE).
Ocamlfind(findlib). http://www.ocaml-programming.de/packages/
Objective CAML 3.08.1 or above.
PCRE library for OCaml.
ExtLib for OCaml. http://ocaml-lib.sourceforge.net/
OcamlNet >= 0.98. http://sourceforge.net/projects/ocamlnet
mod_caml >= 1.3.2 http://www.merjis.com/developers/mod_caml/
OcamlDBI >= 0.9.13 http://www.annexia.org/tmp/ocamldbi-0.9.13.tar.gz
~~GregorianDate. http://www.merjis.com/developers/gregorian_date~~ (since 1.3.12, GregorianDate is no longer required)
Calendar >= 1.09. http://www.lri.fr/~signoles/prog.en.html
PostgreSQL database 7.4 or above.
Postgres bindings for OCaml. http://www.eleves.ens.fr/home/frisch/soft#postgres (Markus Mottl's later version, renamed PostgreSQL, will probably work, but you may need to modify a little bit of the code in scripts/cocanwiki.ml so it connects to the right database using the right driver).
tsearch2 from PostgreSQL contrib
Dimitri Ara's ocamldsort. http://www.eleves.ens.fr/home/ara/ocaml.html
Imagemagick - some of its tools are needed when uploading images.

Things go easier with Debian. Install the following Debian/testing packages, and you should be away:

Experimental debian packages for mod_caml, GregorianDate and COCANWIKI.