Can’t add images

I had to re-install wordpress yesterday as my site had an error and my server company suggested I re-install wordpress which I did via my c-panel and fantastico (ver 2.63).
1 also re-instated my sql database and the site looked to be working fine. (http://themarauder.co.uk)
I’m trying to write a ‘post’ and then add an image but it doesn’t allow me anymore. Prior to re-installing, the add image page would ‘pop-up’ on top of the site and would work, but now it comes up all by itself with a white background and no site and is to the left of the screen, whereas befor it would pop-up in the middle. I fill in the image link and get the green tick but when you go to ‘insert’ it does nothing.

Any ideas on how one can resolve this?

Would appreciate some help.