R.Gasquet:
If I may answer this, it seems that the option to always open this type of file has been selected, and there is no program associated with the .dmo file extension. Basically, instead of prompting you to download the file, Windows is attempting to open it. One easy work around (if it works) is to right-click on the link to the file and choose "Save Target As...." I just tested this with Internet Explorer, and this method seems to work fine. So, instead of left-clicking on the link to the file, right-click on it and follow the step above.