Can not cancel print jobs

I'm unable to cancel print jobs from cups. If I use the web interface at http://localhost:631, I get Error: client-error-forbidden If I try from the "kde printing manager", it allows me to cancel the job, but the printer goes on printing; I have to power cycle it, and usually it tries to continue printing again, maybe a blank page (an inkjet type, with insufficient memory to hold a page in memory buffer). -- Cheers, Carlos Robinson