I’ve been bit by this a time or two… user changes their name in AD, but it doesn’t get updated automatically in Sharepoint via the Profile Import… there is a manual STSADM step needed, as taken from MSDN:
“When user account information is changed in Active Directory Domain Services (AD DS), the User name and Account name information is not synchronized correctly after you import a profile in SharePoint Server 2007″
stsadm.exe -o migrateuser -oldlogin <Domain name\Old user name> -newlogin <Domain name\New user name> -ignoresidhistory