I also got similerv problems (below URI and HANGS VC when using X).
http://www.nvnews.net/vbulletin/showthread.php?t=93596
But,I re-booted with "vga=foo video=vesafb:ypan=pro,nomtrr" , this problem (and VC problems on 100.14.09 w/vesafb) seems to be not happend yet.
Before, I usually boot with "vga=foo video=vesafb:ypan=pro,mtrr:3".
So, I suggest you to test re-booting without mtrr,with vesafb, or re-build kernel without vesafb support.
Regureds,
artanejp.