Comment # 5 on bug 1095144 from Per Jessen

(In reply to Martin Willisegger from comment #4)
> I can confirm that the error message disappears if you enter the map without
> path.
> 
> virtual_mailbox_maps = mysql:mysql_virtual_mailbox_maps.cf
> 
> However, no error message is displayed if you specify a non-existing map
> file - so it is possible that the maps are simply not found in this variant.

Yes, I think that is probably the explanation. 

> virtual_mailbox_maps = mysql:blablubbhaha_mysql_virtual_mailbox_maps.cf
> 
> does also not print out an error message, and this file is not present in
> any path.

Also very weird.