I'm the maintainer for the krb5 and openafs maemo extras packages. Did you compile against the krb5 package from extras? I haven't use SPENGO before, but I have some possible hints. Can you install the LiveHTTPHeaders extension to snoop the traffic? Is NTLM authentication involved? Run "klist -e" and check /etc/krb5.conf to make sure that you have the same encryption types configured as you use on your desktop.