so, followed the install steps - same as guide here: www.debianadmin.com/monitoring-serversnetwork-devices-with-opmanager.html
to install on Debian Etch.
Install went off fine, but running StartOpmanagerServer .sh I got an issue with setEnv .sh not being found.
I changed the path in StartOpmanagerServer .sh to point to setEnv .sh directly, and now the server start ... sort of. It takes about 15 minutes of just sitting there to kick off MySQL, then "inside addon check" appears, then nothing.....