Questions of beginner level

Konnichiwa!

Hi, I'm a japanese student level 1, nice to meet you all. I want to participate in these forums so I can learn more and I can become the number 1 in my class xD. I'm already using a lot the webpage, It is a great source of information for my studies and homeworks :D.

By the way, today I had an exam and I have some doubts about it, I hope you can help me. Here it is:

1.- てんき, いい, きょう, では ありません, は, (the words were scrambled like this, I needed to sort them).

My answer was: きょう てんき は いい では ありません.

2.- Onna no hito wa dou shimashita ka. (there was an image of a girl with stomach sickness, with her hands in her stomach, I needed to answer the question based on that image).

My answer was: Genki dewa arimasen deshita.

Can you help me?

ありがとう ございます。

Your first answer was correct and although your second answer was techinally correct, the question is asking what is wrong, so it was asking for you to say she has stomach ache. 

I hope this helps! I am a second year studying Japanese :)

Your second answer means "she wasn't well", as in at that time she had not been well. I would just stick with present tense and say either げんきではありません。or びょうきです(she is sick)。