Move mailbox task displays current mailbox store but server and destination mailbox store are grayed out for specific user

I am trying to move a user's mailbox from one mailbox store to another mailbox store in a different storage group on the same Exchange 2003 SP3 server, however the drop down menus for server and mailbox store are grayed out in the Move Mailbox Task Wizard.  The only thing displayed is the current mailbox store.  I have checked several other users and can move their mailboxes with no issues so the problem is with this specific account/mailbox.  The account is active and the user is able to log on to the domain and retrieve his mail.  Even though this should not matter for active accounts, I have also tried adding the "Associated external account" permission to SELF under Exchange Advanced/Mailbox Rights as required when moving mailboxes for disabled accounts.  Is anyone familiar with this problem and knows of a solution other than deleting the account, recreating it, and attaching the mailbox to the new account?  I need to avoid doing so if possible.  Thank you.