Every product has limitations.
Please go through the "System Requirements and Supported Platforms for Oracle Business Intelligence Suite Enterprise Edition 11gR1 (184.108.40.206.0" in Oracle Fusion Middleware Supported System Configurations before initiating installation.
Its easy, I had the same problem.
Install the 32bit version instead of 64bit version.
Also before install right click and check the compatibility with others versions of SO. Click on Windows 7 and carry on!! works!