error " Reached end of data when reading"

Hi,

I faced a very strange error related to my COMSOL files. The problem is, when I save a comsol file, I cannot open it again. The message error is “Reached end of data when reading”. I’m sure that there is no problem with my modeling, because I can run it and give the answers and make a report, everything is fine at this stage, but when I save the file and then close it, the problem starts. Because of the mentioned error, I cannot reopen my file. I test this problem for my previous files which I saved them long time ago and reopened them frequently and I had not this problem before. But now, if I reopen them and just click on compute, the modeling runs, and I can give the answer correctly, but when I click save and close the file, I cannot reopen it!
The attached file is one sample of my files which has this problem. You could test it and see the problem.

I will be appreciated if anybody has any comment or suggestion.