no rrd files are generated

I have just installed hobbit.
So i don't know if i have not configurated something..

In the data/rrd directory no rrd files are generated.
In the logs files i see these error:


hobbitd_larrd: error while loading shared libraries: librrd.so.0: cannot
open shared object file: No such file or directory
2005-02-17 17:18:48 Worker process died with exit code 32512, terminating

help!

 thanks.

Marco