My Japanese grammar book states that "-neba naranai" means the same as "-nakereba naranai" and can replace it. It also says that "-neba" is the conditional form of the old negative verb suffix zu or nu. Some examples it gives: 1. もう行かねばなりません。 Mou ikaneba narimasen. I have to leave now. 2. 若いうちはもっと仕事せねばなりません。 Wakai uchi wa motto shigoto seneba narimasen. You must work harder while you are young. It also mentions that example 2 uses the antiquated form "seneba" instead of the more common form "shinakereba". Seneba here matches up with what Kota is saying, I think. :) Thanks for asking this question though because I have never seen this form either and would have thought it should be written like you said (生きなければ) to mean "you have to live". :) By the way, in case you are interested, the book I got this grammar pattern from is "Essential Japanese Grammar : Write and Speak Japanese Like a Native!" by Masahiro Tanimori and Eriko Sato. I don't think any of the other grammar books I have seen include this pattern.

～せねば and ～しなければ are same meaning. 例】行かねばならぬ=行かなければならない。

Thanks for the reply and the information about the movie! Muchas gracias! I will try to watch it as soon as possible! またよろしくね！

Hahaha yeah, I watched in original version with subtitles! The drawing was absolutely superb and the music was fantastic. As touching as the rest of Ghibli films. The plot was good too, but I thought it could have been better, as at some points it gets a little monotonous. I'm sure you'll love it! :)

WOW! You already watched that?!?! I still remember the first time I've wrote about it here as a notebook!!! ( http://www.italki.com/entry/363144 ) I have been waiting for this movie to be released along with the subtitles! I think I will watch it soon too! What do YOU think of this movie? Usually Ghibli movies are always fantastic....Was it the same here too?! (^_^)