layer23 : writing msgb to gsmtap fd: Connection refused

hi, i get errors "writing msgb to gsmtap fd: Connection refused" with layer23 app (see output below). any idea/explanation ? nico nico@debian:~/phone/osmocom-bb/src/host/layer23/src$ ./layer23 -a 4 -i 127.0.0.1 Layer1 Reset. Sending: '01 00 00 00 00 00 04 00 ' SCH: SNR: 6 TDMA: (0609/08/01) bsic: 14 SCH: SNR: 34 TDMA: (0609/18/11) bsic: 14 SCH: SNR: 5 TDMA: (0609/02/21) bsic: 14 SCH: SNR: 218 TDMA: (0609/12/31) bsic: 14 SCH: SNR: 42 TDMA: (0609/22/41) bsic: 14 SCH: SNR: 252 TDMA: (0609/07/01) bsic: 14 SCH: SNR: 148 TDMA: (0609/21/41) bsic: 14 SCH: SNR: 138 TDMA: (0609/06/01) bsic: 14 SCH: SNR: 229 TDMA: (0609/16/11) bsic: 14 SCH: SNR: 203 TDMA: (0609/00/21) bsic: 14 SCH: SNR: 178 TDMA: (0609/10/31) bsic: 14 SCH: SNR: 210 TDMA: (0609/20/41) bsic: 14 BCCH (0609/06/02) 55 06 19 00 00 00 00 00 00 00 00 00 01 ff ff fe 00 00 08 79 00 00 2b l2_ph_data_ind() fmt=Bbis UI RSLms UNIT DATA IND chan_nr=0x80 link_id=0x00 SI1 RACH Req. Sending: '04 00 00 00 00 00 00 00 00 00 ' PCH/AGCH (0609/10/06) 2d 06 22 00 90 17 82 65 6c 10 f4 68 2b 2b 2b 2b 2b 2b 2b 2 b 2b 2b 2b l2_ph_data_ind() fmt=Bbis UI RSLms UNIT DATA IND chan_nr=0x90 link_id=0x00 writing msgb to gsmtap fd: Connection refused PCH/AGCH (0609/16/12) 25 06 21 00 05 f4 9c 04 25 d1 2b 2b 2b 2b 2b 2b 2b 2b 2b 2 b 2b 2b 2b l2_ph_data_ind() fmt=Bbis UI RSLms UNIT DATA IND chan_nr=0x90 link_id=0x00 PCH/AGCH (0609/20/16) 15 06 21 00 01 00 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2 b 2b 2b 2b l2_ph_data_ind() fmt=Bbis UI RSLms UNIT DATA IND chan_nr=0x90 link_id=0x00 writing msgb to gsmtap fd: Connection refused BCCH (0609/05/02) 59 06 1a 00 00 00 00 00 00 00 00 00 00 00 00 00 ca c1 c5 0f 79 00 00 l2_ph_data_ind() fmt=Bbis UI RSLms UNIT DATA IND chan_nr=0x80 link_id=0x00 SI2 RACH Req. Sending: '04 00 00 00 00 00 01 00 00 00 ' PCH/AGCH (0609/09/06) 15 06 21 00 01 00 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2 b 2b 2b 2b l2_ph_data_ind() fmt=Bbis UI RSLms UNIT DATA IND chan_nr=0x90 link_id=0x00 writing msgb to gsmtap fd: Connection refused PCH/AGCH (0609/15/12) 15 06 21 00 01 00 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2b 2 b 2b 2b 2b l2_ph_data_ind() fmt=Bbis UI RSLms UNIT DATA IND chan_nr=0x90 link_id=0x00 ...