first, it might not be your ram. I got these same error messages as well and it turned out to be the size of the still images I was using.
If you have images in your time line make sure they are not super hi-rez or 300 dpi, and I wound try to stick with Jpegs.
If you are using images that are 300 dpi try bumping them down to 150.
Also in your Preferences adobe recommends you change the setting optimize rendering for - "memory" but this means that when rendering Premiere will use as much memory as it can.
So exit out of other programs :)
Hope this helps!