Buttar Challenge: ON or OFF? (#5)

The sender waited patiently for a reply from Rashid, before sending a follow-up e-mail querying as to whether Rashid would keep his word and accept his own challenge:

Date: Fri, 16 Sep 2005 08:00:16
From: [same sender]
Subject: Fwd: Re: Thimerosal Challenge: CONFIDENTIAL to RASHID only/RESENDING
To: drbuttarclinic@...

PLEASE NOTE:

STILL NO REPLY FROM RAHSID BUTTAR.

IS THE CHALLENGE ON or OFF ?