install the FOUR dependencies first, then run configure.pl:

1. front-end: libpcre
2. front-end: libpcap
3. back-end:  rrdtool
4. back-end:  web server (apache)

note: FBSD packages noted here are recent as of Jan. 2008.

note: do not use the ourmon BSD port.  It needs to go away.
**********************************************************
It is too old and out of date.
**********************************************************

Dependencies are:

front-end: 1. libpcre, and 2. libpcap.  You probably have
libpcap.  If there is a compile time problem with libpcap, use
the latest version from www.tcpdump.org

back-end: 3. rrdtool/perl.  
4. You also need a web server  (apache).

details:

1. pcre
get it from
www.pcre.org,  or freebsd port is: /usr/ports/devel/pcre 

advice: either ok:

2. libpcap
www.tcpdump.org, or port is: /usr/ports/net/libpcap

If there is any problem, *IT IS BETTER TO DOWNLOAD FROM www.tcpdump.org*
then to use the port as it is quite likely that the port
version is down-rev a bit.

advice: either ok, BUT when in doubt download from www.tcpdump.org

3. rrdtool

findable at: http://oss.oetiker.ch/rrdtool/download.en.html

port at:
/usr/ports/databases/rrdtool  or possibly 
/usr/ports/net/rrdtool (it may just be sitting there 
as the port moved if you haven't updated your ports)
        
If rrdtool has --enable-perl-site-install in its config
(default), that is what you want.  Else see INSTALL
for details about how to make bin/omupdate.pl work.

advice: either ok

4. apache, 
http://apache.org
port at: /usr/ports/apache*  (your pick ...)

Note:  you need to know the web server directory for ourmon
before you run configure.pl. 

configure.pl will guess:

/usr/local/www/data/ourmon

and then make that directory and put the .html files in it, etc.