SYMLINK

[Christian Walther]

Make sure that your exim data really resides in /usr/var2/exim.
Afterwards, remove /var/spool/exim.
The ln command won't remove any existing files and directories, but it
doesn't complain in this case. And then you have to take care where
you specify source and destination: The source is an existing file or
directory, while the destination is the directory that should contain
the link.
Source is first, destination follows. In your case, the command should be:

ln -s /usr/var2/exim /var/spool/exim

HTH
Christian