Oh that is right! Thank you so much for noticing this, this made the thing work.
However, unfortunately, this is not the end to my troubles. I don't know if I should make another forum post or continue in here ?
Just now, I noticed this error when I'm logged in, at the top of my product's page :
vmError: The chosen template couldnt be found on the filesystem: /home/kobazz/public_html/templates/gk_simplicity

Gk_simplicity is not selected anywhere, I have correctly selected gk_storebox in my virtuemart settings.
Digging through the internet, I've found the information to go to Template Manager for the template I'm using and select the VM menu options under "Menus assignment".
However when I go to StoreBox template, I'm greeted by this:

Not a single template option. If I remember correctly, Gavick always had a tab with template options ?
Please help!