MQTT newbie troubles

lI wonder whether you're connecting to an MQTT-SN server rather than normal MQTT, or something like that?

I'm not sure that understand you right way, do you ask which broker I use? If so, I try cloudmqtt.com and iot.eclipse.org - same result.
And today I have a new problem with my yesterday-somehow-worked code. Espruino can't publish messages now.

Uncaught Error: Field or method "length" does not already exist, and can't create it on Number
 at line 1 col 88
...lish",c),b.emit("message",c.topic,c.message);else if(d!==f.P...
                              ^
in function called from system
 at line 1 col 24
a=g(a);var c=b.length+e.length,d="";do{var f=c&127,c=c>>7;0<...
                       ^
in function "m" called from line 1 col 95
...?l(a):l(a)+d;return m(c,a,b)
                              ^
in function "q" called from line 1 col 42
this.client.write(q(a,b,e||this.C.DEF_QOS))
                                         ^
in function "publish" called from line 45 col 36
    mqtt.publish('/iskra', humidity);
                                   ^

Could it be relevant to last updates? didn't look to changes so far.