After some investigations we found out that Symantec especially included Image Uploader to the threat list in one of their updates. And perhaps unlike killbit, Norton affects new secure version.
I have just posted my suggestions how to handle this to Image Uploader FAQ forum:
http://forums.aurigma.com/yaf_postsm9838_Image-Uploader-and-Norton-Antivirus.aspx
We will definitely make some more detailed investigations on this (what exact builds are affected, etc) and publish additional information in that post. Also, we are going to contact Symantec and try to come to some solution.