Progress Bar is not showing

hi,

in my plug-in, I want to show the progress bar of a operation.I used AIUserSuite(AIUser.h) like ----

sAIUser->SetProgressText(ai::UnicodeString("Progress Bar"));

sAIUser->UpdateProgress(currentOper + 1,max);     // in a loop where currentOper is increasing

since both function does not return any error code so I am enable to get know  what is being wrong . Is there other way to use this? Is this require multithreading?

can any one put write code or any suggesion that can help me to get out of this headache.