No input file selected?

Hey im new to WP just finnaly got it up and going, but when i post and use the <more> option and then try and view it, i get an error that says No input file selected Same thing will happen if from my page i click on achrives, categories and comments!

Im not the most famaliar with .php as i am new to it, but i would appriciate any help that can be offered!

thanks