Question : ADmodify.exe "mailbox rights modification disabled" ??

I was hoping to use ADmodify.exe to modify mailbox access rights for some users, but after selecting a specific domain user, clicking "Next..." and then clicking on the "Mailbox Rights" tab in ADmodify, all rights checkboxes are grayed out, and at the bottom of the window is the message:

"Mailbox Rights Modification Disabled.  Exchange 2000 or later is required."

I'm running ADmodify on the Small Business Server 2008 box--where all of the Exchange 2007 SP1 components (including Exchange System Manager) are running.  (Same result when run on a Server 2008 member server on the same domain.)  It does this regardless of which user I select (or if I select all users).  

It's my understanding that ADmodify should work with Exchange 2007.  Anyone know why I'm unable to modify mailbox rights?

Answer : ADmodify.exe "mailbox rights modification disabled" ??

Yes it should work.
Are you using the latest version of admodify?

http://admodify.codeplex.com/