To upload videos to your iPod, they need to be in MPEG-3 or MPEG-4 format. You can upload some file types to iTunes such as .mpg and .mov and others, but not all. I suggest using Videora iPod converter. You can convert any file type to MPEG-4, which is what your iPod uses. Below is the link for the free download:
http://www.videora.com/en-us/Converter/iPod/
Once you download it, open the program, set it up so that your converted files go to the folder you want (i.e. D:/MyVideos/ConvertedforIpod..or something). Click on convert, click on transcode new video, and browse for the video you want to convert. After it is done, find the converted file, drag and drop into iTunes Movies.
Hope this helped 🙂
Windows XP