$ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $this->url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_USERAGENT, $this->browser);
        curl_setopt($ch, CURLOPT_HEADER, 1);
        curl_setopt($ch, CURLOPT_COOKIE, $this->cookies);
        curl_setopt($ch, CURLOPT_TIMEOUT, $this->timeout);
        curl_setopt($ch, CURLOPT_REFERER, $this->referer);
        curl_setopt($ch, CURLOPT_POST, 1);

        if($this->binary) {
            curl_setopt($ch, CURLOPT_BINARYTRANSFER, 1);
        }
        if($this->file_upload($this->post_data)) {
            curl_setopt($ch, CURLOPT_UPLOAD, 1);
            $p_data = $this->parse_post_data($this->post_data, 1);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $p_data);
        }
        elseif($this->encoded_post) {
            if($this->file_upload($this->post_data)) curl_setopt($ch, CURLOPT_UPLOAD, 1); else curl_setopt($ch, CURLOPT_UPLOAD, 0);
            $p_data = $this->parse_post_data($this->post_data, 1);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $p_data);
        }
        else {
            $p_data = $this->parse_post_data($this->post_data, 0);
            curl_setopt($ch, CURLOPT_POSTFIELDS, $p_data);
        }

        if($this->headers) curl_setopt($ch, CURLOPT_HTTPHEADER, $this->headers);

        if($this->proxy) {
            curl_setopt($ch, CURLOPT_PROXY, $this->proxy);
        }
        if($this->proxy_user && $this->proxy_pwd) {
            curl_setopt($ch, CURLOPT_PROXYUSERPWD, $this->proxy_user.':'.$this->proxy_pwd);
        }

        curl_setopt($ch, CURLOPT_NOPROGRESS, 1);
        curl_setopt($ch, CURLOPT_VERBOSE, 0);
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
        $this->ans = curl_exec($ch);
        curl_close($ch);
        unset($ch);

Для загрузки страницы использую такую функцию. Время от времени скрипт зависает, пытается загрузить страницу и останавливается на curl_exec($ch);. В чем может быть проблема?