I solved the probem by replacing
TDateValue= record
dt: TDatetime;
dts:string;
value: double;
end;
with
TDateValue= record
dt: TDatetime;
dts: ansistring; //<-!!
value: double;
end;
Since Delphi 2009 unicode strings are supported so that the string-type consists of 2 bytes per character. It looks like the TDirectoraclePathloader can not handle unicode strings in my DOA Version.