rxvt: Cannot load color "Black" - Aborting

[George J. Wakileh]

Hello,

I am getting a few warnings as below.  
 
rxvt: Cannot load color "Black" - Aborting

xterm: Cannot allocate color yellow3

Warning: Color name "black" is not defined
Warning: Color name "white" is not defined
Not enough colormap entries available for basic colors - using monochrome mode.

I have rgb.txt in /usr/X11R6/lib/X11/ and it has 
255 255 255		white
  0   0   0		black
205 205	  0		yellow3
etc

Are there any other files having to deal with colours?  If so, what are they and where are they located?

Thanks very much in advance.

Kind regards,

George