In logwatch-5.2.2-1.FC3.1 with perl-5.8.5-12.FC3, the .../scripts/services/exim
script fails to start due to its odd use of "eval .. require" construct, and
thus produces empty log reports.
Changing the line
eval "require Date::Calc qw(Delta_Days)" or exit 0;
use Date::Calc qw(Delta_Days);
makes it work.
This problem should be fixed in the latest logwatch version (logwatch-6.1.2-1).
Could you please try to reproduce this problem with this version.
This problem is fixed in the last devel version (since logwatch-7.0-1)