And just to answer the obvious quesitons, yes, I re-upload and overwrite the file to the server, and then update from the Modules Administration page of the Admin section.
Anyone?
It turns out my hosting provider had done something on the server that houses my database, and it was denying access to my username & password.
So it was also denying access to the XOOPS script running my site when it tried to access the database using that username & password.