Problem with kbName(keyCode), WIN XP

1
Hi,

I am using Psychtoolbox ver. 2.54 on a PC with Windows XP.
I have problems with the functions kbDemo, kbName. When I start
kbDemo I get the following error message as soon as I press a key on
the keyboard :

» kbdemo
1 of 4. Testing KbCheck and KbName: Press any key(s). Press the
escape key to proceed to the next demo.
??? One or more output arguments not assigned during call to 'kbname'.

Error in ==> C:\MATLAB6p5\toolbox\PsychToolbox\PsychDemos\KbDemo.m
On line 63 ==> fprintf(['You pressed key(s) ' int2str(find
(keyCode)) ' which is %s\n'],KbName(keyCode));

Does anyone else have the same problem? I get the same error message
when I use the function EventAvail.
I think that the problem is related to what is given back as the
keyCode by the function kbCheck. When I run this function the keyCode
is an array consisting of 256 zeroes and ones. If I give this keyCode
as an input to the function kbName, I get the same error message:

» a= kbName(keyCode)
??? One or more output arguments not assigned during call to 'kbname'.

Can anyone help?
thanks,
birgit