I did a quick search and found prior SR for the same error.
As you mentioned, the ODBC PeopleSoft PeopleTools driver is installed in PT8.51 by running the PS_HOME\bin\client\winx86\psodbccrinst.exe.
It spools a log under %TEMP%\psodbccrinst.log
Please paste this into the START > Run > %TEMP%
which takes you to the %TEMP% directory.
Once there, open the psodbccrinst.log file and verify.
Its possible to run the executable and see success, but the result may not be as intended.