Here is a summary of events as relates to my box:
-- used nvidia driver before
-- changed to kernel 2.6.30
-- could not install nvidia driver
-- switched to nv driver
-- firefox started to mirror on certain websites
-- changed to slackware-13 kernel-18.104.22.168-smp
-- firefox still mirrors
-- checked firefox in slackware, found OK
-- found slackware uses vesa driver
-- used vesa driver in my box and firefox does not mirror
-- checked driver in Absolute Linux-13.?, it is nv
-- Firefox does not mirror in Abs.Lin-13 with nv driver
-- used Abs.Lin xorg.conf in my box with nv driver and Firefox mirrors.
-- used Abs.Lin xorg.conf in slackware and Firefox does not mirror with nv
-- installed new nvidia driver for kernel 2.6.30 compliments of Uelsk
-- Firefox does not mirror
BTW the version of firefox does not seem to matter. I am using 3.5.5 now
and I think the problem was with the 2 versions as well.
Hope this all will make sense to somebody and help solve the problem.