Entourage partially truncating email addresses

[Abe]

I have sent an email someone with address in the form of
'[email protected]'

I've been careful to not let entourage auto-fill the email address
incorrectly, etc. However, I keep getting the mail bounced back to
me. When I review the bounced mail message, it shows that I had tried
to send the email to '[email protected]' - thus totally removing the
two digit year from the email address.

When I send to this address through outlook, no problem; in Entourage
- it doesn't work.

So I tried to send to someone else with an address such as:
'[email protected]'
In this case, it works, so it has something to do with there being a
two digit number, or numbers after an underscore.

Any ideas?

Thanks.