Works fine this end. I ran your code (using a different table name) to empty out my log_archive table:
mysql_query("DELETE FROM log_archive WHERE id>'50'") or die(mysql_error());
//Rows were deleted
//No rows deleted so do some deleting
mysql_query("DELETE FROM log_archive ORDER BY id asc LIMIT 10") or die(mysql_error());
print 'not deleted';
Took me 5 button clicks to delete the final 50 items so I can only say that your code works.
Are you sure you're on the right server? (Easy to run on one and then look at the database on another - eg localhost and the remote server).