I receive the error below when trying to connect to a Smart Objectin InfoPath with a less-privileged user. It seems to work fine with admin user. I have followed this guide to get cascading drop-downs working in Forms Services.

(I know this is an InfoPath Rich Client Error and not Forms Services: this is just to get more debugging info)

I have the "Allow user account impersonation by the K2 Server" setting set, however I don't know if I need it. Kerberos is configured on the server and appears to be working OK with the sample process.

Does the user account need additional privileges or perhaps delegation set in AD?