ps2 mouse driver problem -- kernel psmintr error messages

[Ed Berger]

With either the liveDVD or installing from CDROM and building X11 from 
pkgsrc, on a HP m8000n media PC I have problems with the mouse cursor, 
which flies to the right side of the screen as soon as its touched, and 
seems to just jump up and down on the far right of the screen when the 
mouse is moved.  The PS2 mouse works fine with linux (centos, opensuse) 
or windows (xp, vista).

It was detected as
kernel:  psm0:  <PS2 Mouse>  irq 12 on atkbdc0
kernel:  psm0: model IntelliMouse, device  ID 3
In the log there are messages, which don't look encouraging to me.
  kernel: psmintr: out of sync (0008 != 0000)
  kernel: psmintr: discard a byte  (1).
  kernel: psmintr: out of sync (0008 != 0000)
  kernel: psmintr: discard a byte  (2).
  kernel: psmintr: out of sync (0008 != 0000)
  kernel: psmintr:  discard a byte (3).
Is there a configuration file I need to edit or is it a bug with the 
mouse driver?

My temporary workaround is to plug in a USB mouse and change xorg.conf 
to use /dev/ums0, instead of using the factory ps2 mouse.

The machine is using an nvidia nforce4 based motherboard with AMD64x2 
processor,   SATA drives, ps2 keyboard and mouse.