I just tried to purchase this Blue Point offer on BitsduJour using Opera with and without SOF. See screen shots P.S. This is an exercise...I may not use the software.
I then tried it in IE6. It went through OK, but I disabled SO, just in case. Afterwards, I took some sample screenshot with Safe Online enabled...just to see. See screenshots. So it has got me beat as to why one browser worked and the other failed.
This sounds more like a bug within their purchase page - I'm unsure how SafeOnline would interact at that level, but if you're still experiencing it, it might be worthwhile to send a scan log to report@prevxresearch.com in case there is something being blocked within your browser. Let me know what you find!