cannot edit the quiz index.html

I'm trying to do the code challenge but I am suddenly unable to type anything within the index.html on the screen. I could type on the first step. Clicked check. Got the green to move forward. Got the next set of instructions but cannot type. I reload the page. Nothing. I Ctrl+F5. I'm back to the first question. I repeat the steps. Get to the next coding step and can't type again.

I'm using Firefox as my browser. This is very frustrating.

update At first I thought that it was because I was copying and pasting the code, so I did it all again by hand. Made a small mistake, scr instead of src... so when I went to check it I got some random off the wall error like "make sure to add img/numbers-01.jpg". [By the by, this is by far the worse error checking training ever. The lessons are awesome, but the code checking is supper confusing and I'd say useless. Code Acdemys error checker is much more direct and clear. I get src wrong and get don't forget to add?? how is that a logical error message...]

Realizing the code was wrong I tried to click into the line to fix it and I'm once again stuck with only the mouse and no cursor... I can't move on. This might make me quit this whole thing if the system tortures me by making me do reload over and over again.

The worst part about this is I'm just trying to get to the Ruby training! I know all this HTML stuff. rage