I run beagled , after a while it always halts

[waterloo <waterloo2005 gmail com>]

It gives :
Debug: Delaying add of file:///media/bak/oo/FILE/??n?¤????????ì???·.chm until FSQ comes across it
**
ERROR:strenc.c:193:mono_unicode_to_external: assertion failed: (utf8!=NULL)
Aborted

how to fix it ? thanks

I use beagle in gentoo on IBM T43 laptop.