It would have puzzled the daylights out of me if I hadn't encountered something very similar a few years ago when another user was tinkering with something a bit outside the box. In short, the underlying lightbox script was seeing that YouTube address and saying, "Hey, I can show that in a lightbox!" Thanks for the favor, but in this case, no.
Launch jAlbum and then
Tools > Open Directories > Skin directory. Then open the skin's
includes folder and replace
folderiterate.inc with the attached version.
I'll put it in the next release, but that might be a while.