Dark frame before stacking...

[Nielsen81]

Hi

I just went outside to try and take some photos of the nightsky.
After a slow start, the camera (a Canon 450D) started taking pics, but when I tried to make some dark frame photos as mentioned in this guide, nothing happened. My camera simply wouldn't take pictures. 
Being a newbie I could easily be some sort of stupid mistake, but what have I done wrong, since it won't take a couple of pics with the lens cap on?

BR
Nielsen

 

[JonC]

If the camera is set to autofocus it will not take a photo if you have the lens cap on, that would be my guess. 

[Nielsen81]

In the menu, where I can choose between "One shot", "AI Focus" or "AI Servo", I have chosen "One shot".

[Nielsen81]

I found out what I did wrong, I believe... Rookie-mistake!

No need to answer my question anymore