I am running the following command on a 64 bit debian system.
chroot /xyz/abc update-rc.d ec2 start 2 3 4 5
I get "chroot: failed to run command `update-rc.d': Exec format error". I dont get this error when the command is executed on 32 bit system.
So I figured out the problem, I was trying to run "chroot" on 64 bit system from a 32 bit machine. Mounting a 64bit FS on a 32 bit system worked, but chroot failed.
Works well if I do the same on the 64 bit FS. Thanks for all the answers.