Please refer to the PostgreSQLpostgres manual for COPY. Note the versions across the top; click on 8.3 for docs that apply to your version of Pgmanual for COPY.
In pgAdmin (or the sql string you pass via a script or other db connection) you would just use COPY with no "" prefix.
so enter something like :
COPY tablename....
You need to make sure that you have the relevant privileges to run the command, so in this case you need to be able to log into the database and have write access to 'tablename'. Postgres also needs to be able to reach the file, so the path /home/uploads/ should be accessible on the database server and the postgres user should be able to read the file - check the permissions to the file and directory.