services won't run on mirrored system

I run FC4. To let a class of students practice being sysadmins, with too
few machines for one each, I want to run several root filesystems
multibooting with shared /usr and /home volume.
(not concurrent, they take turns and don't mess up each others' work)

hda1=/usr hda2=/home hda5=/ hda6=/(2) /hda7=/(3) ...

Created mirrors of / while not live, using dump | restore
Edited each /etc/fstab to mount its own /
Remade each initrd with the new fstab
Edited grub.conf

The mirrors boot up nicely and run apps as user, but it won't load
shared libs as root, to run service, e.g. network & portmap. Gives
error "cannot open shared object file: Permission denied"

When booted into the original installed / the services start fine.

Any ideas please?

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Steve S.