14 of 15 Assets Loaded ???

I am in the middle of a unit with my 7th and 8th grade students using scratch to teach control structure.  This week about 8 of my 60 students are not able to load their projects.  They log in and try to open any project and get stuck with one or two assets short of loading.  A few have been able to wait it out after 10 to 15 min. but the rest never load.  We have been using scratch off and on for the last 5 weeks with no issue so I am at a loss as to why this is happening.

A few things I have tried are...
  Deleting the browser cache
  Logging in from other computers
  Using IE and Chrome
  
We are using windows 7 with IE or Chrome

Any help would be greatly appriciated!