Every year or so, NetDocuments will update its Active X Controller. This is usually not a big deal unless you don’t have admin rights to install programs, or something just goes wrong. If that is the case, you need to download the active x controller and install it.
NetDocuments just did this at the beginning of February 2018, so it should be a while before we have to do this again.
If you are in Europe or Australia, check out this page for your controller.