I can add links via the old "Relate to URL" link or when editing a work, but when I go to add a new work the "Add Link" box seems not to work.

I use Google Chrome on OSX 10.9.1.
Every work I experienced this issue during the adding process were imported from JASRAC via jesus2099's userscript (http://userscripts.org/scripts/show/94676). I attempted to link to a whitelisted database URL via the "Add Link" dialogue box but when the addition edit went through, the URL edit did not.