Store in Marketpress

Hi, I have almost cracked Market Press but have two issues

I have put the store page in main menu (products appears underneath it) but when you click on store it just goes a blank screen and says "Index of Store/Parent Directory" How can this be removed? I really want a store link on the homepage that goes direct to the list guide of products

Also, my shopping cart widget, when I have added something, conflicts with the widgets below as it drops down and it all gets jumbled up. I am using the Max Magazine theme. Any suggestions?

Thanks