Problem with PS2 mouse in Xorg

[Arthur Barlow <arthurbarlow%gmail.com@localhost>]

I just loaded a new version of  NetBSD 5.0 to my Athlon Duron, MSI
motherboard, (KT4 Ultra).  I can enable wsmoused in rc.conf without running
Xorg.  However, when I run X it doesn't recognize my mouse, which is a
Microsoft PS2 mouse.  Here's what Xorg.log.0 says:

(**) Option "Device" "dev/mouse"
(EE) xf86OpenSerial: Cannot open device dev/mouse
            Device Busy.
(EE) Mouse0: Cannot open input device
(EE) PreInit fail for input device Mouse0
(II) UnLoadModule : "mouse"


Any suggestions?