>>I don't think this is a WeBWorK bug. Something is not working with your File::Fetch installation.
OK, I hope we can find it.
>>You can use the OPL-update-legacy script, but that will take a while (around 10 minutes if your computer is fast).
I already did it, it worked, it took about 10 minutes as you said, but the good thing is that the error is gone.
Now to solve other problems, when I ran OPL-update-legacy several errors came out, most of them are of this type that I think are from the Contrib folder that I activated::
But the ones that most concern us for now are these, that although they are displayed well in library browser, when rendering them this error appears