[kde3.5.5] kprinter "connection to cups server failed"

[Liz Young]

Hi list,

Since upgrading to 3.5.5, opening kde print manager shows "initializing 
manager" and then;
"Unable to retrieve the printer list.  Error message received from 
manager:
Connection to CUPS server failed.  Check that the CUPS server is 
correctly installed and running.  Error: localhost: read failed (15)."

lo is up:

# ifconfig | grep lo
lo        Link encap:Local Loopback

and cups is set to listen on :631

# cat /etc/cups/cups.d/ports.conf
Listen localhost:631
#Listen /var/run/cups/cups.sock

and here it is listening:
# netstat -nlp | grep cups
tcp        0      0 127.0.0.1:631           0.0.0.0:*               
LISTEN     10176/cupsd

Any hints?

Thanks,
-Liz