The gallery that was to host an Islamic prayer service led by a woman next Friday has pulled out in the face of mounting threats, including one promising to "blow you up."But organizers said the were determined to go ahead with plans to challenge the Islamic prohibition against women leadind mixed-sex prayers. After scrambling to find a new venue, they said late Friday that they had decided to limit participants to an invitation-only list for security reasons, but to broadcast the event on the Internet and through the media.'snip"Organizers seemed taken aback by mounting threats, especially against the backdrop of...