Can't Update Ubuntu 9.04

[John Graddy]

I have a solid red circle with a horizontal white line at the top of the
screen (notification panel?) in Ubuntu 9.04.  I'm not sure when it first
appeared.  When I put the mouse cursor over the circle, I get the pop-up
message "A problem occurred when checking for the updates."  If I click
the circle, I get a VERY BRIEF flash on the screen which looks like the
notification that comes up when updates are available.

If I try to bring up the update manager (system>administration>Update
Manager) the same thing happens.When I attempt to execute synaptic in a
terminal as a non privileged user, I get a message that I can't apply
any changes (and some other stuff) and then I get a segmentation fault.

If I execute synaptic in a terminal using sudo synaptic, my password is
requested and then I get a segmentation fault.

If I do sudo apt-get install update, my password is requested and I get
Reading package lists... Done
Segmentation faulty tree... 0% 

Several other users have reported the "red circle" notification on
another Ubuntu forum.  There has not been a solution given.  I'm afraid
that, if a fix comes out, I will not be able to install it.  In the
meantime, I drop further and further behind.

Has anyone else seen this error?  Is there a solution?

Thanks,
John