To avoid troubles with none-ascii file and folder names a patch has been released.
Download the patch from:
Save the current version of the file "$OBEXTOOL/lib/obexfile.tcl" - it will be overwritten by this procedure.
Unpack obexfile-0.4.1.tgz  in the ObexTool main directory - eg:
  tar -xzvf obexfile-0.4.1.tgz
Warning: the existing file "lib/obexfile.tcl" will be overwritten!
Restart ObexTool...

It should now handle german "Umlaute" correct.