[EXIM] Failed to open wait-remote_smtp database: what does …

Colleagues

In /var/log/exim/mainlog, I see the following:

2001-07-31 13:33:19 15RXm3-0000al-00 <= root@phimail U=root P=local S=574

2001-07-31 13:33:19 15RXm3-0000al-00 Failed to open wait-remote_smtp
database: Invalid argument                 
2001-07-31 13:33:19 15RXm3-0000al-00 => pieter.vankeerberghen@???
R=smarthost T=remote_smtp H=phimail.
2001-07-31 13:33:19 15RXm3-0000al-00 Completed     

There is an alias between root@phimail and myself and phimail is the
internal MS Exchange email server. Exim is set up using Phimail as the
smart host.
Mail gets through but what does the 'Failed to open wait-remote_smtp
database' mean ?

Thank you in advance,
Pieter