I am not an expert on WordPress or translation files. But I have been using those translation files without any problem. So my guess is that the problem is elsewhere. However, I have looked again at the translation files, made a few cosmetic changes, and tried the new files out again. Still no problem.
Yoav, you can try the new files below. Perhaps they will work better for you, although I think your problem is more likely to be resolved by downloading and installing the Suffusion theme again.
Sayontan, please use this updated set of Hebrew translation files for your next release.