The reason you can't cook is because you need to start off with some low-level food (shrimp)
Fish them and then cook.
And the reason you can't do RC is because you have to have the rune essence in inventory and you have to use it at a certain part of the runecrafting alter. If your on sometime that I am on I will show you where. But, incase your not on when I am, I will try to explain it. Look at the green sign on the fence thing. Just walk straight to the alter from there.