when trying to open oracle bi administration tool client, You can download oracle bi administration tool client from here.
Most probably this error related to version mismatch between OBIEE Server and Administration Tool Client in my case OBIEE Version 126.96.36.199.1 and Administration Tool client 188.8.131.52.0
1- Download Upgrade Patch 17530796 From http://support.oracle.com depend on operating system
2- Patch contain multiple file search for this one :- p17463403_111170_Generic.zip
3- inside this zip file browse
4- you will find two files biee_client_install_x64.exe Or biee_client_install.exe depend on version.
5- Install One of this file to upgrade Administration tools, Use Repair Option.