NOTE: OBIEE 11g (11.1.1.3) BI Administration Tool does not work under Windows 64-bit OS. It is expected that the next release of OBIEE 11g (11.1.1.4) will support 64-bit Operating Systems for the OBI Client applications. But Presentation Services work with the present release. So, think twice before you take decision to install 11g(11.1.1.3) on 64-bit OS.
So, if you have decided to install on 64-bit machine…follow these steps:
This installation post is going to be series of 3 parts. This is the first of the 3 posts.
Part-1 –> Download software and configuring RCU (Repository Creation Utility)
Part-2–> Installing OBIEE 11g
Part-3–> Configuration
Part-1:
Download OBIEE 11g(11.1.1.3.0) software and RCU(for 32 bits)from here. As there is no RCU for 64bits, download the 32bits one and it works)
also download RCU 
Once you download all the files, extract them and keep them under one directory(Keeping RCU in the same directory is not mandatory, just for convinience).
Before starting the installation keep your have got database up and running. RCU will create two schemas in the installation process…
First step of installaton is running RCU (Repository Creation Utility), go to C:\Software\OBIEE11gR1\bishiphome\rcuHome\BIN and double click on rcu.bat file.
Welcome page of the installation wizard will open …click Next. Select Create
Click Next
Enter all the required information, be sure that the database user has got sysdba previlages…Click Next
Click OK
Enter the Prefix (or leave the default one DEV) and select the components install…
Click OK and enter the passwords for all the users (2 users) that created in the following screen…
Click Next
Click OK
Click OK
Click Create
Click Close..we are done with RCU
…till next time