Hi
I finally found a solution :)!
I installed the 64-Bit client from Oracle and configured the system-DSN in the ODBC Administrator (64 Bit). After that I changed the typ of the DTS-importjob from ORACLE to ODBC (screenshot).
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And thats it!
After that I got a new bug that we can't configure the changed DTS-importjobs because the "weiter"-Button (next-button) is not working anymore. But the import is working now.
Best regards
Florian