when trying to open oracle bi administration tool client, You can download oracle bi administration tool client from here.
Cause :-
Most probably this error related to version mismatch between OBIEE Server and Administration Tool Client in my case OBIEE Version 11.1.1.7.1 and Administration Tool client 11.1.1.7.0
Solution :-
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
17463403\files\clients\biserver\
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.
Thank you
Osama Mustafa