Adding users to a Virtual Server (failed)

Please refer to
Submitted by JamieCameron on Sun, 12/06/2009 - 12:23 Comment #11

I followed these steps in Virtualmin, (with the correct website selected) and failed with:
“Failed to save custom shells: No shells were selected for resellers”

I have no resellers, why is this necessary. What should I do?
I would like to give another user Mail, SSH & FTP permissions.
Currently I can only select Mail & FTP or FTP, sFTP & SCP

We are trying to move a wiki that has been migrated to dokuwiki over to the permanent server.
The wiki is quite large.

Thank you.

PS: Also, can this be undone later without problems, after we get the wiki transfered?