PHP / Youtube API while-loop problem

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PHP

YouTube

cycle

PHP code for counting views. Code below works properly only with a very small db. For example, db with 300 rows gives multiple errors:
Warning: file_get_contents(https://gdata.youtube.com/feeds/api/videos/xxxxxxxxxxx?v=2&alt=json) [function.file-get-contents]: failed to open stream: HTTP request failed! HTTP/1.0 403

Here is the code:

while($query = mysql_fetch_array($myquery)) {
    $video_ID = $myquery['url'];
    $JSON = file_get_contents("https://gdata.youtube.com/feeds/api/videos/{$video_ID}?v=2&alt=json");
    $JSON_Data = json_decode($JSON);
    $views = $JSON_Data->{'entry'}->{'yt$statistics'}->{'viewCount'};
    $viewsCount += $views;
    sleep(1);
}

Also tried to use sleep(1); at the end of the loop. It works, but unfortunately, not stable.

This helping to prevent error with script execution time (20-30sec):

ini_set("max_execution_time", 0);