Amjad I have tried the above but the problem is that on some machines it shows the portfolio ananlyzer view and on some it give the same message saying
"Unable to access the Microsoft Office Project Portfolio Analyzer OLAP cube
The cube may not exist, or you may not have permissions to access the cube.
I will tell you stepwise what I have tried uptil now
1) I have added the computers users on the domain that need access to the portfolio analyzer, as administrators on the machine where both project server and analysis server are installed
2) I have added all these computer users, in the databsase roles in the analysis server instance of the project server
3) I have given these computer users administrator rights in project server itself which gives full rights on protfolio analyzer as well
But still for example one of these users when connects from his machine cannot access the portfolio analyzer view. Another thing to be noted is that we are using windows user authentication for project server as well
Let me know if you have anything else in mind.