Not recognizing the IE message dialog

[adpbinu]

QTP 9.5 Build 194 and testing a web application (DNN application).
The action is to delete a user. When clicking on the Delete button, application displays a confirmation message, which is an IE dialog with OK & Cancel buttons. When recording the action, it added the following line of code:-

Code:

Browser("User Accounts").Dialog("Microsoft Internet Explorer").WinButton("OK").Click

But when running the test, it gives an error message saying "Run Error. Object is not visible......."

Thanks,
Binu.