Has it to be a .rar file to demonstrate the problem? The point is to create some trivial example that other monks can use to reproduce the problem and thus help solve it.

It seems likely, as others have pointed out, that you have a line end tanslation problem and that controlling the binary/text mode of the file will fix the issue. But if it is something else you should try to find a way to reproduce the problem with a small piece of code. Just the process of finding a minimal example of the problem may will make the solution clear to you.