How to fix print error in windows form application

Hi,

I have joined your website as a new member. I am new in programming. I have developed a windows form and created a print function using the tutorial code on the your website. Everything was successful at design time but when I clicked the print button at runtime the was an error message I couldn't fix. Please can anyone help me fix it?

 

Attached is the error message and the code.

Thanks for your usual assistance.