[CentOS] Help with TCL/TK on centos 5.2 unknown color black

Hi all,

I am using centos 5.2 x86_64 on a box. and getting this error:
 wish -f pcalert.tcl
Error in startup script: unknown color name "black"
    (processing "-background" option)
    invoked from within
"canvas .c -height $canvas_height -width $screen_width -background black 
-highlightthickness 0 "
    invoked from within
"set c [canvas .c -height $canvas_height -width $screen_width 
-background black -highlightthickness 0 ]"
    (file "pcalert.tcl" line 138)


I take the same script on 3 other machines with centos 5.2 x86_64 and it 
runs just fine.
What is the machine that gives the errors missing that is doesnt know 
what black is???

Thanks,

Jerry