Syslinux - Nov 2005 - kernel not starting

I'am having trouble with pxelinux for this machine/netcard combination
IBM PIII 6564-r3u 640 megs ram  (note kernel approx 1.4 meg rd 240 meg)
3com 3c905c-TXM
The problem is after the menu loads and the kernel and ram disk is 
decompressed I get a message that says OK starting kernel. But the kernel 
does not start. With my other machines the kernel starts fine.

I have tried other kernels and the latest pxelinux.0. I was wondering if 
this maybe a known issue and what to do inorder to fix.

here is  /pxelinux.cfg/default

label 7
   kernel bzImage-2.6.11.12
   append ramdisk_size=256000 root=/dev/ram0 rw initrd=fcs-rd.gz

thanks,

Jeff Geddes