firefopx startup error

[steve%prd.co.uk@localhost (Steve Blinkhorn)]

Stock 7.0 on three different machines: attempt to run filrefox.

(process:22127): GLib-CRITICAL **: g_slice_set_config: assertion
'sys_page_size == 0' failed
Xlib:  extension "RANDR" missing on display "body:1".
/usr/X11R7/lib/libXext.so.7: Undefined PLT symbol "_XGetRequest"
(symnum = 99)

Can anyone construe? provide a cure?

-- 
Steve Blinkhorn <steve%prd.co.uk@localhost>