Addi Circular Express Help Please!!!

[Chiminee]

Let me start by humbly saying that you all obviously know so much more than I ever will about knitting, so forgive my inexperience and inability. I bought an Addi Express Circular King Sized Knitting Machine for my 7 year old daughter and me to play with. I watched online videos, and we made an amazingly cool hat and a scarf on Christmas day. But today we tried the same venture, same yarn, and we broke two needles and we have run into a problem with yarn getting really tight and bunching up. Does anyone have any experience with this problem and could you offer any advice please?