Hi,
I don't have a ULIFAC myself so I can't test the solution. I have been told that you need to extract the files from the .dsk using winape: 'A good way to get them is the Winape Dsk Editor (CTRL+SHIFT+F1) and show Sys files' (to be sure to see hidden files). To select all the files, select the first one then the last one while holding shift. Then right-click->copy and past in your folder. I tried recreating the floppy from the extracted files and it works. So there is some chance that it solve your problem. Let me know if it helps :)