You can in your gallery forum settings make sure your forum url is correct and also in your vbulletin settings double check this as this is where we get th url depending on where in the code we are at. You can also sign into your vbulletin admin and go to styles management and under the global style options for your particular style change the relative paths to redirectories like so
/images/buttons
to say this
http://forum.mydomain.com/images/buttons
although I doubt a missing image is going to keep your box from appearing.