By reading though posts this appears to be a very common and some people have been able to solve it by putting their OracleDataAccess.dll and support files in the same folder as the exe. However, I tried putting the OracleDataAccess.dll, oci.dll, ociw32.dll, orannzsbb11.dll, and oraocci11.dll in the folder and the problem persists.
This application works fine on my development system (Windows 7 64, VS2010 SP1) and 2 of our 3 servers (Windows 2008 R2). But on this one server it does not work! The problem first appeared when a developer installed ODT with ODAC 112030 on server. We installed a full version of the 188.8.131.52.0 Oracle Client (this matches our other servers) and removed the clients created by the ODT with ODAC 112030 install. However, I fear there is something somewhere that was not deinstalled causing the issue. Any thought on how we can track down and eliminate this problem.