If the installation process went fine, the necessary SafeControl entries should be added automatically to the web.config associated with the SharePoint web application you are testing. Please check the following in your SharePoint environment:
1. Launch Central Administration page and navigate to Operation -> Solution Management and make sure Quest Shared Web Parts.wsp solution package exists in the solution package store.
2. If solution package does exist, click on the solution package and ensure it has been successfully deployed to the web application you are testing; otherwise, try to deploy it from Central Admin page.
3. You can always manually add the Safe Control entry to the web.config. First make a backup of the web.config and open it using your favorite editor.
4. Locate the element tag <SafeControls> or <SafeControl>
<SafeControls>
…
<SafeControl Namespace="WA.Core.Editor" Assembly="WA.Core, Version=4.0.0.0, Culture=neutral, PublicKeyToken=2b4b09f1c57c8f0b" TypeName="*" Safe="True" />
<SafeControl Namespace="WA.WebPart" Assembly="WA.WebPart, Version=4.0.0.0, Culture=neutral, PublicKeyToken=2b4b09f1c57c8f0b" TypeName="*" Safe="True" />
</SafeControls>
5. If you do not see SafeControl entry with Namespace to "WA.WebPart", please add it to the configuration file.
6. You should now be able to go back to the page and add qDiscussionView web part. In most cases, iisreset is not needed.