Ok i started trying to learn how to render and i been using the tutorial and i got to stage 4 and it said click render buton i did that i get this

How can i fix it

Cheers

That's a limitation of the Brazil trial, you can't save your renders fullsize
There is a plugin that takes care of this, basically it just renders several parts of your render at 512*384 and puts it together afterwards to make the whole picture.
It's called Bigrenderer or something but I have no experience with it and i don't know if it works well.

get Bigrender here. click on Rendering on the right side of page.
http://www.scriptspot.com/start.htm

put BIGRender in the plugins Folder.
Press 8 this will bring up Environment and Effects.
Press Effects button, and then the Add button.
you will see BIGRender2 DEMO click it and click ok.
at the bottom BIGRender Parameters. is the width and height of your pic.
and then you have Subdivision. in the 1st one put in 2 and the 2nd put in 3
go down to Save AS and make a Folder, and then click Render.