We are very sorry that we have not developed 7.91 based NimBUS Robot.exe.
There are 2 ways for you to perform install.
A) Add the latest release of "robot_exe" package to your archive, and deploy the robot over USM.
B) Add the latest release of "robot_exe" package to your archive, and deploy the robot over ADE (host-profiles.xml)
Let me know any questions.
Regards,
Yu Ishitani