Photoshop won't save as pdf

I have a big problem. Suddenly my photoshop won't save as PDF, and i don't know what to do. 

I hope you can help me. 

This is what it's doing when i try to save it. 

And then it's just shut down. 

Is there a solution to this that I am unaware of? i don't have a printer installed on my computer

I hope you will and can help me.