Exclamation Mark - but only at 58% capacity

Please review this prezi for the exclamation mark. It should only be 58% of my capacity but is not allowing access. I need to use it this evening. Thanks!
http://prezi.com/hcpc6fs3iq8j/sf/

It was working again by late afternoon, and allowed for edits and use, but the error I keep running into is that my prezi’s will simply go to white screen and an exclamation with a circle around it and it won’t allow for edit or play in that state. When I would go to the Settings page it would tell me that there was still plenty of room, but if there’s an exclamation mark it won’t allow for anything. Fortunately, I was able to complete the edits on that one and use it as needed last night. Thanks.