[xubuntu-users] Package manager error

[Phil]

Thank you for reading this.

An error icon (a red circle with a white bar through the centre) is 
showing on the status bar that, when clicked on, pops up a message that 
reads, in part:

"An error has occurred. Please run Package manager from the right-click 
menu or run apt-get in a terminal to see what is wrong."

Is this a known problem that will be corrected with an update? If not, 
how should I correct the error?

I don't know where the right-click menu is and I don't know what options 
are required to run apt-get.

Both Software Updater and Ubuntu Software Centre fail.

-- 
Regards,
Phil