Are you trying to access it in an internet browser? If so, you don't need IIS to do this.
Is it a fresh install of SSRS you've just made, or is it one that was working previously?
As a silly question, you have checked that the user that is used to connect to the server in the ReprotServer configuration tool has access to the ReportServer Database on the SQl server?
Thom~
Excuse my typos and sometimes awful grammar. My fingers work faster than my brain does.
Larnu.uk