undefined symbol: dect_mm_endpoint_get

Hey, my Asterisk got a problem with the chan_dect module. I build it like it's written here: http://dect.osmocom.org/trac/dect/wiki/Build%20instructions

debian*CLI> module load chan_dect Unable to load module chan_dect Command 'module load chan_dect' failed. [Aug 10 14:23:41] WARNING[19284]: loader.c:449 load_dynamic_module: Error loading module 'chan_dect': /usr/lib/asterisk/modules/chan_dect.so: undefined symbol: dect_mm_endpoint_get [Aug 10 14:23:41] WARNING[19284]: loader.c:839 load_resource: Module 'chan_dect' could not be loaded.

Could someone help me, getting this fixed?