Additional content for Premiere Elements 7 can be found by following the link in the article linked to at the end of this FAQ.
You'll need to log in to your Adobe account, and then you'll see the link to the download on the same page as the Free Trial download.
John Venediger received this from Tech Support, based on his problem installing additional content (including templates and themes):
When trying to install/open the contents file (PRE7_Cont_WWEFGJ) you get this message - The setup has detected that premiere elements is currently in use. Please close Premiere Elements, then launch setup again despite the fact that Premiere Elements is not in use.
To resolve this issue, please perform the following steps:
1. Right-click the Microsoft® Windows XP® taskbar and select Task
2. Under the Applications tab of the Task Manager, please ensure Adobe
Premiere Elements or Photoshop Elements is not running in the background.
3. If Adobe Premiere Elements or PhotoShop Elements is running in the background, please
select the application and press End Task.
4. Next, switch to the Processes tab and look for a process named Adobe
Premiere Elements.exe. and Photoshop ElementsEditor.exe.
5. If Adobe Premiere Elements.exe or Photoshop ElementsEditor.exe. is running, please select the process and press End Process.
If you are still unable to install the additional content, please refer
to our knowledge base document kb404997. Perform step 8 and try the
installation again. Continue to step 7 if necessary. To access the
document, simply copy the following and paste it in the address bar of
your web browser: