Error 500! (Steam Error 26)

[PLItEng]

`<?php require_once('classes/steam.class.php');

$steam = new SteamTrade(); $a=$steam->setup( "51638**", "sessionid=156786**; steamLoginSecure=****%7C%7C****" );

$itemsFromMe = array( array( "appid" => 730, "contextid" => "2", "amount" => 1, "assetid" => 302**** ) );

$c = $steam->makeOffer(array( 'partnerSteamId' => '76561****', 'itemsFromMe' => $itemsFromMe, 'itemsFromThem' => array(), 'message' => 'TEST', ));

var_dump($c);`

Error making offer! Server response code: 500

[PLItEng]

response: object(Unirest\Response)#2 (4) { ["code"]=> int(500) ["raw_body"]=> string(89) "{"strError":"There was an error sending your trade offer. Please try again later. (26)"}" ["body"]=> object(stdClass)#549 (1) { ["strError"]=> string(74) "There was an error sending your trade offer. Please try again later. (26)" } ["headers"]=> array(10) { [0]=> string(34) "HTTP/1.1 500 Internal Server Error" ["Server"]=> string(6) "Apache" ["Vary"]=> string(22) "Accept-Encoding,Origin" ["Content-Security-Policy"]=> string(506) "script-src 'self' 'unsafe-inline' 'unsafe-eval' https://steamcommunity-a.akamaihd.net/ https://api.steampowered.com/ *.google-analytics.com https://www.google.com https://www.gstatic.com https://apis.google.com; object-src 'none'; connect-src 'self' http://steamcommunity.com https://steamcommunity.com https://api.steampowered.com/; frame-src 'self' http://store.steampowered.com/ https://store.steampowered.com/ http://www.youtube.com https://www.youtube.com https://www.google.com https://sketchfab.com;" ["Expires"]=> string(29) "Mon, 26 Jul 1997 05:00:00 GMT" ["Cache-Control"]=> string(8) "no-cache" ["Content-Length"]=> string(2) "89" ["Content-Type"]=> string(31) "application/json; charset=utf-8" ["Date"]=> string(29) "Mon, 18 Jul 2016 10:59:24 GMT" ["Connection"]=> string(5) "close" } }

There was an error sending your trade offer. Please try again later. (26) Error 26 means the partner's inventory is full or the item is already in a trade. But I not sent anything to trade yet. And partner inventory is almost empty.

[emdy]

Ez to make curl php and dont use this dumb lib.