That makes little sense, unless host esx03 doesn't have the Essentials Plus license applied to it or it's a version of ESX that isn't supported by the 5.5 license.
The only vMotion option that does not come with Essentials plus is the ability to move the VM to different storage alone.
Moving to a different host or, as mentioned, to both a different host and storage are both specifically supported by Essentials Plus.
What version of ESX is running on that particular host?
I'm no expert, but if the host is not running 5.x, it may not support live VM movement under that license.