function addgeometrycolumn("unknown", "unknown", integer, "unknown", integer) does not exist?
This is a common problem that usually means you don't have the postgis functions loaded in your database. The easiest way to remedy are
1) If you are starting with a new database and you have a database called template_postgis - create a new database and choose the template_postgis as your template
2) If you already have a database with tables, spatially enable your database by running the following SQL files Postgresql\8.2\share\contrib\lwpostgis.sql Postgresql\8.2\share\contrib\spatial_ref_sys.sql