If it is this message indicates that somehow the traffic is coming "encrypted" to the asa but there is no SA created to decrypt it, go ahead and add the line that I mentioned and turn on "debug crypto isakmp 15" and try again. Post your debugs here if unsuccessful.
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...
Table of Contents 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 an...