Email -Check Names?

Hi,
Can someone help me?
I'm trying to email out a report (HTM file) using vb. i've created an instance of Outlook to do this. However when I put in the email addresses, I keep getting a Check Names dialog box, it can't find the names. I click Cancel, wait a few seconds and suddenly the names are found and I can email (click Send). Any ideas? Obviously I don't want this box to appear everytime, and I don't know why it does - the email address are all valid addresses.

Any ideas??

[email protected]