Hello,
links on /etc/munin/plugins/ shouldn't contain "-" character, if munin server is configured with "graph_strategy cgi", it can't draw the graphs.

apache error log shows:
Warning: Weird scale setting "cputime-day". Bailing out.
Premature end of script headers: munin-cgi-graph

at /usr/lib/cgi-bin/munin-cgi-graph line 67 uses "-" as a separator, then plugin name can't contain it

best regards,
Lluís

Dear Maintainer,

I have run into this problem too. It's really just a matter of replacing the dash with
an underscore. Dashes are forbidden because all field names in munin must only contain
the [a-zA-Z0-9_] characters:
http://munin-monitoring.org/wiki/notes_on_datasource_names

One can also rename the plugins at the time of creating the /etc/munin/plugins symbolic
link but having dashes in the original filenames is really entrapment.