The new BusinessObjects 4.0 platform runs on 64bit OS. In an oracle based environment, this can be the source of much confusion. While the platform itself (the CMS and Audit databases connections) support 64bit oracle driver connectivity, other BO tools do not. For example, the client tools, Universe designer or Crystal Reports 2011 are 32bit applications and will work only with 32bit versions of the oracle driver. So, what is one to do? Well, if you are looking to have the client tools installed on a server (in a development environment for example), or are deploying crystal reports that leverage oracle 32bit client connectivity, you will need to install both the 64bit and 32bit version of the driver on the machine, and in the same home. Once you get both clients installed and configured, you will be able to use applications that need 32bit middleware as well as applications that requires 64bit middleware.
In the example above, the 64bit client is installed into the dbhome_1 directory and the 32bit driver is installed in the client_32bit directory. Both are part of the same oracle home.
To keep things simple, make sure both clients share the same oracle home, as shown in the picture below, and make sure the tnsname.ora file is configured properly on both clients. To test your configuration, make sure you execute the tnsping.exe and/or sqlplus.exe commands from each directory separately to assure both clients are working properly and can connect to your database.