Popup Window

Back again guys;

I followed the instruction to open a popup window according the instruction in the video of Kirupa. Everything is working correct. Put it inside of my webside and two pages are still working ok, but one of the pages is loading a large fragment of the whole site inside the popup. If I click the properties of ‘show all’ it will show me the whole image. I checked the instructions, copied everything as I did with the other pages and suddenly it won’t work?

Someone an idea what I did wrong?