The pk3 only contains textfiles, no picture, no shader, only text: 
  
  
pb_nocdkey.cfg: 
 
set ui_finalURL "http://etkey.org"
 
  
  
ui\popup_errormessage_pb.menu: 
 
#include "ui/menudef.h"
// Defines //
#define WINDOW_X		0
#define WINDOW_Y		0
#define WINDOW_WIDTH	640
#define WINDOW_HEIGHT	480
#define GROUP_NAME		"grpPopupError"
// Macros //
#include "ui/menumacros.h"
// Error Popup //
menuDef {
name		"popupError"
visible		0
fullscreen	0
rect		WINDOW_X WINDOW_Y WINDOW_WIDTH WINDOW_HEIGHT
style		WINDOW_STYLE_FILLED
popup
fadeClamp	0.5
fadeAmount  0.075
onOpen {
	uiScript ServerStatus_diagnose ;
	setitemcolor background backcolor 0 0 0 0 ;
	exec "set cl_noprint 1;exec pb_nocdkey.cfg;set cl_noprint 0"
	fadein background
}
onESC {
	uiScript clearError ;
	close popupError ;
	open main
}
// Background //
itemDef {
	name		"background"
	rect		0 0 640 480
	style		WINDOW_STYLE_FILLED
	background	"ui/assets/fadebox.tga"
	backcolor	0 0 0 0
	visible		1
	decoration
}
// Subwindows //
#define SUBWINDOW_WIDTH		256
#define SUBWINDOW_HEIGHT	292
#define SUBWINDOW_X			.5*(WINDOW_WIDTH-SUBWINDOW_WIDTH)
#define SUBWINDOW_Y			.5*(WINDOW_HEIGHT-SUBWINDOW_HEIGHT)
SUBWINDOWBLACK( SUBWINDOW_X, SUBWINDOW_Y, SUBWINDOW_WIDTH, SUBWINDOW_HEIGHT, "ERROR" )
CVARLABEL( SUBWINDOW_X+6, SUBWINDOW_Y+16, (SUBWINDOW_WIDTH)-12, 154, "com_errorMessage", .2, ITEM_ALIGN_LEFT, 0, 8 )
LABEL( SUBWINDOW_X+6, SUBWINDOW_Y+160, (SUBWINDOW_WIDTH)-12, 80, "For Empty-CD-Key Error and / or missing punkbuster files look on http://ETKEY.ORG",.2,ITEM_ALIGN_LEFT,0,8 )
BUTTON( SUBWINDOW_X+10, SUBWINDOW_Y+SUBWINDOW_HEIGHT-48, .5*(SUBWINDOW_WIDTH-18), 18, "^7Visit ^1ETKey.org", .23, 11, close quit ; close ingame_main; uiScript validate_openURL )
BUTTON( SUBWINDOW_X+6, SUBWINDOW_Y+SUBWINDOW_HEIGHT-24, .5*(SUBWINDOW_WIDTH-18), 18, "BACK", .3, 14, uiScript clearError ; close popupError ; open main )
BUTTON( SUBWINDOW_X+6+.5*(SUBWINDOW_WIDTH-18)+6, SUBWINDOW_Y+SUBWINDOW_HEIGHT-24, .5*(SUBWINDOW_WIDTH-18), 18, "RECONNECT", .3, 14, uiScript clearError ; close popupError ; close backgroundmusic ; close background_1 ; uiScript reconnect )
}