Most of the processes of NME are working properly; such as mail migration, directory export, find NABs, mail routing, merge contacts, etc. For this specific issue, Mailbox-enable existing Active Directory accounts process was causing the Notes client crash.
The NME server is Windows 2008 R2 with Notes Client 7.0.1. This was an environment specific issue.
Notes client 7.0.1 installed on Windows 2008 R2 server.
Windows 2008 R2 server is not a supported operating system version for Notes Client 7.0.1
Downgrade to an operating system that is a supported operating system with Notes client 7.0.1 such as Windows XP
Upgrade the Notes client to a supported version with Windows 2008 R2 operating system.
Refer to IBM Article - "Notes and Domino 7.0.1 platforms and system requirements" for more information.