[syslinux] why boot intsallation stops

[hong zhang]

Dear List,

I try to generate a generic boot disk for various versions of Redhat. When the disk boot up, user can chose one of Red Hat version to install through network. boot.iso in first disk starts installation. But if I do 
following in isolinux.cfg as following, 

kernel /boot/vmlinuz
append initrd=/boot/initrd.img 

after boot up and installation will stop (Normally, it should start a process of installing kernel) like this

......
ACPI: PCI Root bridge [PCI0] (00:00)
PCI: Probing PCI hardware (bus 00)

Do I miss something here?
Thanks.

---henry