zlos: THANK YOU!
I had to add that &postid=$thread[postid] to get it working myself... just one little change to the image_adsense template (just pasted the snippet I changed)
Code:
<div><center><img src="$vboptions[bburl]/attachment.php?attachmentid=$attachmentid&ads=1&d=$time&postid=$thread[postid]" border="0" alt="" /></div></center>
It showed ads for a few minutes, but now it's not working... Very odd!