Unknown Database Connector Error in Crystal Reports

Ok, I am probably just shooting air with this question.. but I have no idea what's happening and I have been banging my head against it for the last couple days.

I have a crystal report version 12.2.0.290... I built this report against an Oracle connection string (not ODBC as it was giving me errors to use a stored procedure as a data source). Anyway, so the report was connecting to the database fine.. and I was able to build the entire report.. refreshing data with every change I made etc.. Once I was finish开发者_Python百科ed.. I closed the crystal report. When I open the report again and try to refresh the data I get the error "Unknown Database Connector Error in Crystal Reports". I get this error when I try to run the report straight from crystal reports.. or from the .NET wrapper that we built for this report. I also get the same error when I run the report (in CR) from another machine. In fact I get this error just trying to connect to an any Oracle database from that report..

The really strange thing is that if I open another report that we built a while ago.. I can connect to the same exact data source from it and it I go to File -> Open and open the first report.. I can connect to the Oracle data source and the report runs fine.. I can reproduce this strange behavior at will.. I don't know what is going on.... and I have been staring at this problem for the longest while.. if anyone has any ideas I will be more than happy to try them out...

Thanks!!

This is The Resolution:

https://social.msdn.microsoft.com/Forums/vstudio/en-US/d2811b33-2c2c-43d1-af51-9c54e9ad7920/unknown-database-connector-error?forum=wpf

I've fixed the problem, I just needed those lines:

<startup useLegacyV2RuntimeActivationPolicy="true">
  <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
</startup>

If using a stored procedure as your data source, make sure it RETURNS a RESULT SET. Once I added a 'SELECT * FROM dbo.mytable', the error went away. :-)

Are you using the latest Oracle Data Access Components?

How to check which version you are using:

• During installation of ODAC, consult the ODAC Installer screen.
• After installation, see the history.html file in your ODAC installation directiory.
• At design-time, select Oracle | About ODAC from the main menu of your IDE.
• At run-time, check the value of the OdacVersion and DACVersion constants.

_{Note: This was originally a comment but added as an answer after OP response on how to check for the version of ODAC}