PHPMailer: Cannot override final method Exception::__clone()

Using latest version of PHPMailer (5.2.7)
PHP v5.3.10
jQuery 1.8.2
jQuery Mobile 1.3.0

I am writing a Web program in PHP that sends a text message to a mobile device. The initial message may be instigated from a normal Web page or a jQuery Mobile page. After receiving the message, the recipient selects a link that goes to a Mobile page, and pulls up the record saved from the original form that instigated the initial message. The recipient then responds through a radio button selection, which saves to the database and sends a text message to the originators cell phone. That person then responds back.

Intermittently, when that response is made, PHPMailer errors out with the following message:
<b>Fatal error</b>:  Cannot override final method Exception::__clone() in <b>/home/best/public_html/m/PHPMailer/class.phpmailer.php</b> on line <b>3297</b>

At 3297 in PHPMailer is the following (starting at 3292):

/**
 * PHPMailer exception handler
 * @package PHPMailer
 */
class phpmailerException extends Exception
{
    /**
     * Prettify error message output
     * @return string
     */
    public function errorMessage()
    {
        $errorMsg = '<strong>' . $this->getMessage() . "</strong><br />\n";
        return $errorMsg;
    }
}

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It seems that something is held in a cache somewhere (or  ???) because once this error occurs, it will continue to fail whenever another attempt is made, even when the process is started from the beginning. It seems like this times out after a while.

In testing, I have gone back and forth as much as 20 times with no errors. At other times it errors on the first response back to the original recipient.

I am totally at a loss.