Dear Marco,

thanks for your quick reply. Maybe one more point I didn't mention before (sorry): Some path seems to be set incorrectly during installation of DOA tools. First error I get when I drop an OracleSession on my test form is 'Unable to open include file Oracle.hpp'. After that, I add the path to include->vcl manually in project options, now it works. Then, when I drop an OracleDataSet on my form and OracleData.hpp is required, the afforesaid error (ambiguity) occurs.

Thanks and regards

Martin