I installed 11g. Then VStudio 2008.
I figured out that I forgot to install Oracle Database Extension for .NET, so I run Installator and added it.
That'd be all.
I have another question but this goes to another thread
I spent some time in reproducing this problem but I could not! I tried custom installation and custom database options but the entries were all fine. However by installing ODE component later, I could not automatically get the tns/listener entries created (such as ORACLR_CONNECTION_DATA) etc.
By any chance did you upgrade from 10gR2 to 11g database? Or was it a fresh installation?