[Exim] Having some problems with domains and POP boxes...

Hi there

I was wondering if anyone would be able to help me fix a little problem I'm
having

I want to add an e-mail box for simple collection.. Easy enough to make a
new account for the user, but when i go to try to send e-mail to the
address, I get:

    unknown local-part "spaced" in domain "champions-of-marr.com"

while when I send to spaced@??? (other name, same IP), it
goes through OK.

What config bit am I missing??

Thanks,

Tim