That happens when you click the preview button as there is not a temapte screenshot delivered in the template package.
In your shop admin> Tools > Template Selection...
Click the edit button for whatever template is currently installed. Then choose Acadame in the 'Template Name' drop down list. And then click the update button. The template should then be installed for you. (yes, the process is not intuitive).
If Acadame does not show up in the template name list then the Acadame template package was not copied into your shop directory correctly.
Be aware I have noted some issues with the Acadame template. Specifically the header, missing the standard home, login/logout, my account and shopping cart links menu bar.
And SSL is not activated when visiting the shopping cart page.
But it is a nice looking streamlined 2 column template.
iChoze/testuser has a forum for supporting the Acadame template on his commercial site (ichoze.net) but last I looked it was full of spam.
It appears the free template which can be downloaded from his site is updated version of the Acadame template available in the ZC downloads area.