unknown key released?

[Dj YB]

Hello,
I see many lines all over the /var/log/messages like the below.
what is causing this and how do I fix this (if it is a problem) or stop this?

Thanks in advance,
YB.

Dec  5 14:30:39 localhost kernel: atkbd serio0: Unknown key released 
(translated set 2, code 0x81 on isa0060/serio0).
Dec  5 14:30:39 localhost kernel: atkbd serio0: Use 'setkeycodes e001 
<keycode>' to make it known.
Dec  5 14:31:40 localhost kernel: atkbd serio0: Unknown key released 
(translated set 2, code 0x81 on isa0060/serio0).
Dec  5 14:31:40 localhost kernel: atkbd serio0: Use 'setkeycodes e001 
<keycode>' to make it known.
Dec  5 14:34:57 localhost kernel: atkbd serio0: Unknown key released 
(translated set 2, code 0x81 on isa0060/serio0).
Dec  5 14:34:57 localhost kernel: atkbd serio0: Use 'setkeycodes e001 
<keycode>' to make it known.
Dec  5 14:34:57 localhost kernel: atkbd serio0: Unknown key pressed 
(translated set 2, code 0xd9 on isa0060/serio0).
Dec  5 14:34:57 localhost kernel: atkbd serio0: Use 'setkeycodes e059 
<keycode>' to make it known.
Dec  5 14:36:01 localhost kernel: atkbd serio0: Unknown key released 
(translated set 2, code 0x81 on isa0060/serio0).
Dec  5 14:36:01 localhost kernel: atkbd serio0: Use 'setkeycodes e001 
<keycode>' to make it known.
Dec  5 14:38:02 localhost kernel: atkbd serio0: Unknown key released 
(translated set 2, code 0x81 on isa0060/serio0).
Dec  5 14:38:02 localhost kernel: atkbd serio0: Use 'setkeycodes e001 
<keycode>' to make it known.
...