Load a map in map_server

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And how can I load a map into the map server?
I'm calling:

<node name="map_server" pkg="map_server" type="map_server" args="$(find p2os_nav)/simple_office_map.svg 0.1f"/>

in the launch file but I get this error:

[map_server-1] process has died [pid 12465, exit code 255].
log files: /home/camilla/.ros/log/8b409eb6-5feb-11e2-b202-000fb0a0b12e/map_server-1*.log

and nothing is published on the /map topic. Any ideas? Cheers!