Cannot %include in CentOS 5.5 kickstart

I've previously used includes in CentOS 4.4 and they worked fine.

But in CentOS 5.5, trying to specify a driver disk via an include
does not work.

If I instead specify it directly, it loads fine.

When it fails (because it can't see the disk drive - needs the
driver disk to see the hard disk), in Console 2 I can see that
/tmp/drvdisk exists and has the line I wrote to it.  I see
nothing that looks wrong in any log or kickstart file/fragment in
/tmp.

Any ideas? Here's my complete kickstart to show/test this:


# Minimal Kickstart test for CentOS 5.5 to show %include problem

url --url=http://10.0.4.157/cblr/links/CentOS5.5-i386
text
lang en_US.UTF-8
keyboard us

timezone --utc America/New_York
install
bootloader --location=mbr
clearpart --all --initlabel
network --device eth0 --bootproto dhcp
firewall --disabled
selinux --disabled

rootpw --iscrypted \$1\$x6z.qvwE\$7Zg9g1rCEgvOBoA7Oo/HF1
zerombr
authconfig  --useshadow  --enablemd5

part /boot --fstype ext3 --size 100 --asprimary
part / --fstype ext3 --size 1 --grow --asprimary
part /var --fstype ext3 --size 10000
part swap --recommended


# This does not work
%include /tmp/drvdisk

# This works
#driverdisk
--source=nfs:10.0.4.157:/srv/cobbler/RHEL5.5_x86_402_409_410_DD.img


%packages
@base
@core

%pre --erroronfail

echo "driverdisk
--source=nfs:10.0.4.157:/srv/cobbler/RHEL5.5_x86_402_409_410_DD.img" >
/tmp/drvdisk

(end of kickstart file)