Thanks for your response.
Yes, I am refering to the add a resource url. I have used this feature to
make use of a series of mp4 lectures that I had uploaded on the host I am
using for my moodle courses. They are large mp4 files but they all went
smoothly into each of the modules I constructed. Only since coming back
after a couple of months of a summer vacation do I find myself locked out.
A student noticed that 2 files were duplicated, so I tried to change the
url address there to the correct video and got this message "Sorry, none of your current repositories can return external files" (this message is where the buttons for the enabled repositories are normally located on the left side of the file picker, instead of the normal choices I had seen on the file picker before.
I tried to add a new resource in other modules of this course with the same
results. Then I tried other courses on our site and found that I couldn't
get connected to any repositories --I get the same response as above. I did
enable and make visible google docs, as you suggested, but that didn't change anything.
Thanks for any other ideas you might have or find.