To me it looks as though the error comes from a missing value in the logon details for the FTP server. Have you verified that both username and password were entered correctly?
As for upgrading, I would upgrade the ASA first to version 9.1(3) and then upgrade the SSP-20 module. When it mentions upgrade to 9.1(1) and then to 9.2(1), this is just a minimum version to be able to upgrade to the next level. So if you upgrade to the highest build within a minor version, it will support upgrade to the next minor version.
You still need to follow the upgrade path but as mentioned, it is a minimum requirement to be able to upgrade to the next step.
Tested upgrade paths are for the most recent build number for a given version, and sometimes the second
most recent build. For example, upgrade from 9.1(1) to 9.1(3) is tested with build 9.1(1) Build 21; 9.1(2)
to 9.1(3) is tested with 9.1(2) Builds 29 and 42. To ensure the best results, you should upgrade to the
most recent build for the release you are running before upgrading to a new version.
Thanks again. I was asuming the error was related with the update but in fact it was that the ASA module did not like to connect to a ftp server with a user and blank password. Giving a password to the ftp user resolved that.
Finally i got the desired update. This is the path i followed:
update ASA version 8.4(6)
(with ASA on 8.4(6)) update CX from 9.0.2 (103) To 9.1.2 (29)
(with ASA on 8.4(6)) update CX from 9.1.2 (29) To 22.214.171.124 (48)
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...