Which NS version?
Which OS version?
IF you can use the new NS 7.0.x with your OS, I'm guessing it willl bring a happier result. It is true that it's waaaay faster and more stable than its predecessors.
OTOH, if you haven't done some "heavy" maintenance (just kidding!) on your OS recently, that might account fort some of your difficulty(ies). (Check your e-mail.)
With respect to importing Favolrites into Bookmarks, all you need to do is to save your roster of favorites in an dot/html file, then go to the appropriaste roster in your NS, and Import.
Piece of cake . . . except, as I recall, NS doesn't really sort out duplicates during the importing, so that you will have to accomplish that task by hand.