There are two problems with running Minecraft on the n900, a port of lwjgl to opengles, and a recompile for both libs to run on arm(?).
It looks like the lwjgl you're using isn't ported to opengles. However lwjgl has already been ported, and an arm compilation of jinput also.

Pretty much everything is done, feel free to make a new thread though I doubt many of the users won't care too much for it.