what does not an online contact mean

[SLC]

I am using Office 2003, I am trying to send email but I keep getting them
returned and when I highlight address it says it is not an online contact.

 

[Brian Tillman]

I am using Office 2003, I am trying to send email but I keep getting
them returned

What does the non-delivery report say?

and when I highlight address it says it is not an online contact.

This means that you have Person Name tags enabled and the contact has no
entry in the "IM address" field of the contact form - they're not in your
Windows Messenger buddy list. See "Enabling Instant Messaging" in Outlook's
Help.