Ok. Here it goes. I'm having this same problem and I'm not sure what I'm doing wrong. One. I have multisite on a local install with Mamp on Mountain Lion.
I have buddypress is network activated. Then I go to activate my template pack and my entire site disappears. Meaning I'm navigated to my site and it's a blank page....
It reappears when I delete the template plugin but so does my wpmudev dashboard plugin.
after deleting I get this 'The plugin bp-template-pack/loader.php has been deactivated due to an error: Plugin file does not exist."
which obviously is from deleting it. I'll then drag and drop it back into the plugin folder and it runs again. But I'm not sure what tIm doing wrong. Is there a step I shouldn't be doing?