This is a known bug that we are working to resolve - but fortunately it's pretty easy to workaround. It's caused by having a Model in your page where you didn't select an Object Name. The error handling here is not working (that's the bug), but the fix is this:
1. From the Skuid header, under "compose", select "all pages" to go to the list of Pages. 2. Find your page in the list, and click the Versions icon next to it. 3. Click the "Restore this Version" button next to the most recent Auto-Save version of your page. 4. Click "Edit Page". This will open the Page Composer, and you should be able to interact with your page again.