aboutsiluan on "Insert Gallery button doesn't work"

Hello,

i tried uploading some images from my gallery, but the Insert Gallery button doesn't do anything.. now i have inserted the images but i manually wrote the code in HTML mode.. why doesn't the button work? i want to do tha images on 3 columns and I'm trying to figure it out, but i'm kind of lost..
here's the blog:
http://www.aboutsiluan.com/diagnostic/

thank you!