Comment 14 for bug 33173

Still the same here: however you did not have to use web interface at all. Just ignore the reported error and configure one printer anyhow - this worked for me and when at least one printer was added, this problem is not reported anymore.

I think the missing (private) API that kdeprint uses was added back just recently (rc1) and cups in Dapper still looks to be on Beta1 state.