If I view an ebay listing through FireFox the main listing body is not displayed in it's place is a black box that says "Website blocked by Netgear Firewall", but:

1. I don't have website blocking enabled on my router
2. It happens only in FF, page displays correctly in IE & Chrome

A line from the router's log:

Fri, 2013-02-08 17:15:35 - TCP Packet - Source:121.1.0.90,49991 Destination:vi.raptor.ebay.com,80 - [BLOCK]

This has only started happening in the last couple of months, I upgraded the firmware last week which seemed to have cured it, but it hasn't.

Any ideas? I can't stand IE and I'm not overly fond of Chrome.