Line #144 of OpenThreadImpl.java[1] causing issues;
htmlFileURI = htmlFileURI.resolve(htmlFileName);
This resolves the file name incorrectly, when identifier contains "../path/to/ref.html". Thus, causing serious problems in navigation, returns null reference of FileObject (Line #155).
http://kenai.com/projects/nbrcp-kolektiv/sources/incubator/diff/nbplugins/trunk/ahrefhyperlink.revamped/src/com/wp/nbguru/ahrefhyperlink/revamped/OpenThreadImpl.java?rev1=80&rev2=81