DStream on windows 10 :issue CLI33

Hi

 I used to launch regression scriipts from python scripts and DStream commands

On windows 7 , no problem but on windows 10, it sounds something is missing in the default installation or configuration

Basically  I have a command launched from a cmd windows which is

self.cmd_str += "debugger --cdb-root " + self.CONFIGDB_EXTENSION + " --cdb-entry " + self.DS5_CONFIG_SCU + \
    " --cdb-entry-param " + self.DS5_ADDR + " --continue_on_error=true --image " + \
    os.path.join(self.REG_TC_DIR, module, tc_name, self.device_name + "_" + tc_name + "_scu.elf") + \
    " --script=" + script_ds + " --log_file=regtest.log"

with some variable assigned dynamically.  Iload a elf file along with a Debugger script DS file , with a specific path for the DB 
So when launching this
os.sys(self.cmd_str)
the first message  I have is :
ERROR(CLI33) Failed to Find the default logging file for level: {0}
So all the log done by my ds script which is:
# show debugger version
show version

memory 0x00000000 0x7FFFFFFF noverify
...

I also have issue when  I try to dump memory to the drive

# dump a dummy file to inform elf has been loaded
dump memory elf_loaded.tmp 0x20000000 0x20000004
In that case  Ihave the following error message:
ERROR(COR108) " Dumping memory to "elf_loaded.tmp" [100%]
# in ....while executing :dump memory elf_loaded.tmp 0x20000000 0x20000004
! unable to write image "C:\Progam File\DS-5-v5.27.0\bin\elf_loaded.tmp

I have a DStream ST, and DS5 version is 5.27.0
Any clue on error code would help understand the real cause.
Do we have to do some extra steps on windows 10 to configure DStream/DS5 ?

thanks in advance 
claude