After the 2007 to 2010 SharePoint upgrade i have taken notice that when i try to activate a feature under the site collection admin for a root site page and also with manage site features i keep on getting an error page as mentioned below.

```
<configuration>
         <system.web>
           <custom Errors mode="Off"/>
        </system.web>
    </configuration>

```

I am confused as to why this problem would is occurring.