[Dovecot] Several errors

[FraNL]

> The directory/files are owned by wrong user, or you have set wrong
> user to userdb. v1.2 gives better error messages here.
> http://wiki.dovecot.org/UserIds


Yes, that is also what I figured out. But I am still not a Linux guru
(don't tell me anything about Windows, but Linux is still very foggy to
me). I googled a lot on chown, chmod, permissions, uid, gid and so on, but
I have not a clue how I can change the permissions on a directory, I even
don't know if I have to change permissions on /var/mail/vhosts, or
/var/mail/vhosts/mydomain.tld or /var/mail/vhosts/mydomain.tld/user or
/var/mail/vhosts/mydomain.tld/user/new - and whatsoever....

When looking in /etc/passwd, I can see a user:
dovecot:x:101:202:Dovecot IMAP server:/usr/libexec/dovecot:/sbin/nologin

I hope you can help me!

Albert van Harten
Denmark