I downloaded syslinux from kernel.org
I then did a
find -type f -exec grep -Hn pxelinux.cfg {} \;
from the root of the syslinux folder
to find where gpxelinux.0 started look in pxelinux.cfg
it returned
./syslinux-4.03/core/fs/pxe/pxe.c:1077:    const char *cfgprefix = "pxelinux.cfg/";
I changed it to
./syslinux-4.03/core/fs/pxe/pxe.c:1077:    const char *cfgprefix = "gpxelinux.cfg/";
recompiled everything
and copyied gpxelinux.0 to
/tftpboot/ploplinux directory
I created a directory /tftpboot/ploplinux/gpxelinux.cfg
I pointed my webservers home directory to /tftpboot/ploplinux
/tftpboot/ploplinux/gpxelinux.cfg/default looks as follows
default vesamenu.c32
prompt 0
timeout 300
menu background splash.png
menu title welcome to plop linux
menu color border 	37;40 	#00000000 #00000000 none
menu color title  	1;37;40	#00000000 #00000000 none
menu color tabmsg  	40;37	#88888888 #00000000 none
menu color sel  	1;37;42	#ffffffff #ff808080 none
menu color unsel  	1;40;32	#ff00ff00 #00000000 none
label local
menu label localboot
localboot 0
label linux
menu label plop linux
kernel http://192.168.1.252/kernel/bzImage
initrd http://192.168.1.252/kernel/initramfs.gz
append vga=1 smbmount=//192.168.1.252/ploplinux
label memtest
menu label ^memtest
kernel http://192.168.1.252/memtest
the localboot is just a test for gpxelinux as it fails on more machines than pxelinux's localboot. (I haven't found a machine that pxelinux's localboot fails but I have heard of it.)
and my /tftpboot/ploplinux/pxelinux.cfg/default looks like so
default vesamenu.c32
prompt 0
timeout 30
menu background splash.png
menu title welcome to plop linux
menu color border 	37;40 	#00000000 #00000000 none
menu color title  	1;37;40	#00000000 #00000000 none
menu color tabmsg  	40;37	#88888888 #00000000 none
menu color sel  	1;37;42	#ffffffff #ff808080 none
menu color unsel  	1;40;32	#ff00ff00 #00000000 none
label local
menu label localboot
localboot 0
label test
menu label test
pxe gpxelinux.0
label linux
menu label plop linux
kernel kernel/bzImage
append initrd=kernel/initramfs.gz vga=1 smbmount=//192.168.1.252/ploplinux
label linuxfb
menu label plop linux framebuffer mode
kernel kernel/bzImage
append initrd=kernel/initramfs.gz vga=0x318 smbmount=//192.168.1.252/ploplinux
menu separator
label hd
menu label ^boot harddisk
localboot 0x80
append -
menu separator
label plp
menu label ^plop boot manager
linux plop/plpbt.bin
label plpinst
menu label plop boot manager installer
linux plop/plpinstc.com
menu separator
label memtest
menu label ^memtest
kernel memtest
			
			
			
				thanks
best regards
elmar