Is file writable? If not try to to make it so...

isWritable.php

<?php

/**
 * Check if a file/folder is writable. If not, the function tries to make
 * it writable.
 *
 * @param string $file
 * @param string $mode
 *
 * @return File
 * @access public
 */
function isWritable($file, $mode = 'auto')
{
    if (is_writable($file)) {
        return true;
    }

    if ('auto' == $mode) {
        $mode = 0644;
        
        if (is_dir($file)) {
            $mode = 0755;
        }
    }

    return @chmod($file, $mode);
}