Xubuntu 8.10 w/ backported 4.4.3. 0.4.0 built against libburn 0.5.8 and libisofs 0.6.12. Without thunar-vfs (and with HAL), Xfburn is unable to properly drag & drop symlinked files. Hanging and crashing is the result. Dragging & dropping of non-linked files are a hit and miss proposition. Building with, or without gstreamer does not impact drag & drop stability. Building with HAL and thunar-vfs appears to have solved problem.
Obviously it should not hang and/or crash, I'll look into that. But drag and drop from an outside application does require thunar-vfs, whether it's a symlink or not and that's unlikely to change any time soon.
I think the hang/crash is caused by bad behavior in gtk. Gtk does not like it when a drag and drop which is in the acceptance list does not add anything to the view - which was the case when thunar-vfs is not enabled. In rev. 6737 this is changed now so that without thunar-vfs drag and drops from outside applications (uri-list) are simply not accepted anymore. Note that I certainly recommend to always use hal and thunar-vfs.