Failure of rpmdrake/urpmi and other applications

Mandriva 2010.1, x86_64, stock kernel

The Powerpack DVD arrived at last and I installed Mandriva 2010 Spring 
on a laptop, partly as a test, and just as well.  Major problems ensued.

The installation was a breeze, the smoothest and quickest ever.  My new 
Nova DVB-T USB stick worked out of the box, hot pluggable too.  Added 
sources through EasyURPMI.  Me-TV installed fine and worked perfectly.  
Ruby and Ruby-Tk up and working within an hour.  Closed down and next 
day booted up and tried the update applet, which showed a red 
exclamation mark (that is not right is it?) and attempted to update 
rpmdrake as instructed.  That failed and every attempt at using urpmi  
came up with the message that rpmdrake needed to be updated first.  Each 
time it failed.  So how come urpmi worked immediately post install but 
fails now?

Every failure is accompanied by a symbol lookup error from perl:

libnssutil3.so undefined symbol PL_ClearArenaPool.

The same error is posted from firefox, which fails to start.

To get back to the update applet: it pops up with an invitation to 
update the system every now and then but always fails on trying to 
update rpmdrake.  This happens again and again and each time the update 
program crashes with some complex error which I have not recorded but 
which had something to do with perl5 and the user interface.

Since updating a system after an install is the most fundamental of 
issues I would be grateful for any help in this area.

Len