Internet-Explorer：外部文本文件仅以二进制格式提供

I am having trouble with a strange situation. The problem does always ocurres in Internet-Explorer only. My problem: at my work I have developed a webiste with javascript and css. All javascript sourcecode and css rules are outsourced in external files. For my suprise the javascript code and css rules haven't been invoked. I checked the responsible files, by downloading and opening them into a text editor. When I opened the files they were all in binary format. Remember: only in Internet-Explorer. In Chrome, Safari and Firefox doesn't exists this problem.I am having trouble with a strange situation. T