Xorg:1282 conflicting memory types

[Liunx]

my os info:
Linux liunx-ubuntu 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:24 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux
my vga card info:
00:0d.0 VGA compatible controller: nVidia Corporation C61 [GeForce 7025 / nForce 630a] (rev a2)
when i update my firefox package to 5.0, i get this message:
[ 546.576748] reserve_memtype failed 0xc1e9e000-0xc291c000, track write-combining, req write-combining
[ 546.577627] Xorg:1282 conflicting memory types c1e9e000-c291c000 uncached-minus<->write-combining
Is it a bug?
regards

[Liunx (liunx163)]

May be it's my first encounter of this bug, or i do not care it before, i hope these info will be useful.
regards