Obivously, I cannot know, either, why your posted sample file does not agree with your description of the file. You might download/open your file directly from post #3 and make sure it uploaded correctly.

As I thought about it, perhaps your question is about why skup2 does not show up at all on a "line without markers" plot. I notice that your "hidden and empty cell" setting is set to leave "gaps" in the plotted line where there are "gaps" in the data. Since skup2 is mostly "gaps", there is nothing to plot here. Perhaps what you are looking for is someone to point you to the "hidden and empty" cell setting where you can set it to "interpolate" or "connect" across gaps. If you are using 2003 as your profile indicates, this setting is in the Tool -> Options -> chart tab dialog. If you are using 2007+, this dialog is accessed from the "Select Source Data" dialog.