Sybase did provide us a 64 bits version of the driver. It has been installed on the server. However, we still have the same problem because the 32 bits version of the driver is stillt here and it seems this is the one that is being taken. We cannot remove the 32 bits version of the driver because this is needed for another application. The server is 2008 so how can we force our ASP.NET application to use the 64 bits version of the driver?