please register your Oracle.DataAccess to GAC
raProvCfg.exe /action:gac /providerpath:C:\oracle\product\11.2.0\x32\ODP.NET\bin\4\Oracle.DataAccess.dll
OraProvCfg.exe /action:gac /providerpath:C:\oracle\product\11.2.0\x64\ODP.NET\bin\4\Oracle.DataAccess.dll