Node.js INSERT into postgres error

I have following node.js + express code which is inserting data into postgres.

app.post('/register', function(request, response) {
    pg.connect(connString, function(err, client, done) {
        if(err) response.send("Could not connect to DB: " + err);
        client.query('INSER INTO clients (client_id, params) VALUES ($1, $2)',
            [request.query.client_id, request.query.params], 
            function(err, result) {
                done();
                if(err) return response.send(err);
                response.send('OK');
        });
    });
});

The table structure is:

CREATE TABLE clients
(
client_id character varying NOT NULL,
params character varying[] NOT NULL,
id integer NOT NULL DEFAULT nextval('clients_id_seq1'::regclass),
CONSTRAINT clients_pkey PRIMARY KEY (id)
)

If I do a plain SELECT it works well. However on INSERT I get this HTTP 200 response:

{
 "name": "error",
 "length": 86,
 "severity": "ERROR",
 "code": "42601",
 "position": "1",
 "file": "scan.l",
 "line": "1044",
 "routine": "scanner_yyerror"
}

This error does not say too much for me.