installing fails

Hi,
trying to install Gnumed-Server (newest, PostgreSQL15), but it fails:
(bootstrap-latest.log the first error message )
....

2023-09-22 14:37:42  DEBUG     gm.db_pool    [140273691701248 
MainThread]  
(/var/lib/gnumed/Gnumed/pycommon/gmConnectionPool.py::log_conn_state() 
#874): executing async op: False
2023-09-22 14:37:42  DEBUG     gm.db_pool    [140273691701248 
MainThread]  
(/var/lib/gnumed/Gnumed/pycommon/gmConnectionPool.py::log_conn_state() 
#874): type: <class 'psycopg2.extras.DictConnection'>
2023-09-22 14:37:42  INFO      gm.bootstrapper  [140273691701248 
MainThread]  
(/var/lib/gnumed/server/bootstrap/./bootstrap_gm_db_system.py::connect() 
#295): successfully connected
2023-09-22 14:37:42  ERROR     gm.bootstrapper  [140273691701248 
MainThread]  
(/var/lib/gnumed/server/bootstrap/./bootstrap_gm_db_system.py::__bootstrap() 
#644): cannot fingerprint template database
Traceback (most recent call last):
   File "/var/lib/gnumed/server/bootstrap/./bootstrap_gm_db_system.py", 
line 641, in __bootstrap
     text = gmPG2.get_db_fingerprint(conn = self.conn, eol = '\n')
   File "/var/lib/gnumed/Gnumed/pycommon/gmPG2.py", line 483, in 
get_db_fingerprint
     curs.execute(cmd)
   File "/usr/lib/python3/dist-packages/psycopg2/extras.py", line 146, in 
execute
     return super().execute(query, vars)
psycopg2.errors.InvalidSchemaName: schema "gm" does not exist
LINE 1: SELECT md5(gm.concat_table_structure())
                    ^
2023-09-22 14:37:42  DEBUG     gm.cfg        [140273691701248 
MainThread]  (/var/lib/gnumed/Gnumed/pycommon/gmCfg2.py::get() #396): 
option [template version] not in group [database core] in source [file]
2023-09-22 14:37:42  WARNING   gm.bootstrapper  [140273691701248 
MainThread]  
(/var/lib/gnumed/server/bootstrap/./bootstrap_gm_db_system.py::__create_db() 
#840): cannot check template database identity hash, no version 
specified
2023-09-22 14:37:42  INFO      gm.bootstrapper  [140273691701248 
MainThread]  
(/var/lib/gnumed/server/bootstrap/./bootstrap_gm_db_system.py::__db_exists() 
#831): Database [gnumed_v2] does not exist.
2023-09-22 14:37:42  DEBUG     gm.cfg        [140273691701248 
MainThread]  (/var/lib/gnumed/Gnumed/pycommon/gmCfg2.py::get() #396): 
option [tablespace] not in group [database core] in source [file]
2023-09-22 14:37:42  INFO      gm.bootstrapper  [140273691701248 
MainThread]  
(/var/lib/gnumed/server/bootstrap/./bootstrap_gm_db_system.py::__db_exists() 
#828): Database [gnumed_v2] exists.
2023-09-22 14:37:42  INFO      gm.bootstrapper  [140273691701248 
MainThread]  
(/var/lib/gnumed/server/bootstrap/./bootstrap_gm_db_system.py::__create_db() 
#923): Successfully created GNUmed database [gnumed_v2].
2023-09-22 14:37:42  INFO      gm.bootstrapper  [140273691701248 
MainThread]  
(/var/lib/gnumed/server/bootstrap/./bootstrap_gm_db_system.py::connect() 
#282): trying DB connection to gnumed_v2 on localhost as postgres
2023-09-22 14:37:42  INFO      gm.db_pool    [140273691701248 
MainThread]  
(/var/lib/gnumed/Gnumed/pycommon/gmConnectionPool.py::_set_database() 
#183): [gnumed_v2]
...

Any hints? Thx in advance from Munich, BG