What happens when you connect more than one client?
Are these two clients behind the one router doing NAT/PAT? If so it's probably that the NAT/PAT device isn't NAT/PAT'ing the IPSec traffic properly. If the first one disconnects when the second one tries to connect then this is more than likely the problem, nothing to do with the PIX.
Try connecting from two different locations and see if that works.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
[toc:faq]Introduction:This document describes details on how NAT-T
works.Background:ESP encrypts all critical information, encapsulating
the entire inner TCP/UDP datagram within an ESP header. ESP is an IP
protocol in the same sense that TCP and UDP are I...