If you enable worksharing, your links are contained in worksets. If you update a linked file and want to reload the link, the workset in which the link is located must be editable. If it is not, an error message appears indicating that the link could not be updated because of the workset's non-editable status. See Making Worksets Editable.
It is good practice to assign a team member to track links and be sure the appropriate worksets are editable. After updating the link, the team member should synchronize with central so that all team members have the updated link. See Saving Workshared Files.
Also, you may want to create a workset exclusively for links, so that workflow is not interrupted. See Setting Up and Managing Worksets.