As you know, if you want to show reports created by Microsoft SQL Server 2005 Reporting Services in a SharePoint website, you need to first download and install an add-in from Microsoft official website. However, this installation probably will fail. The symptom is you can't see the report server section as you expected. To solve this problem, you can do the following things as I did:
1. Check the Reporting Services installation log. This log is normally in the %temp% folder, but please notice, it's in an upper folder of %temp% because %temp% will direct you to a number named folder such as "1", its parent folder normally will be named as "temp", that's the folder I mentioned here.
2. In the folder I mentioned in step 1, there normally will have several files named as RS_SP_0.log or RS_SP_1.log, it depends on how many times you installed or uninstalled the add-in. Check the log file with the biggest number.
3. The first line of the log file is something like: User: SYSTEM. This specified the user used for installing this add-in. And in 7 or 8 lines below it, you could probably see a line saying "******* User does not have permission to add feature to site collection: http://yourwebsite:80". If so, this article will be useful for you.
4. Now you can open your SharePoint administrator UI, in "Application Management", choose "site collection administrators", change the web application to the one it mentioned above that has no permission, and add the user name in the first line of the log in. Then you can try to install again, check the log file again, there should have no permission error anymore, and you should be able to see the report section in your administrator UI.
That's it, hope this is useful for you!