Data Series Line in XY Scatterplot Chart print issue

[BillSaffian]

I have several worksheets with XY scatterplot charts created in Excel 2003. There are twelve columns of data presented in the chart with each data set represented by a different line style, color, thickness etc. In the 2003 version, all lines/styles are present in the chart, in print preview and when printed. Now have Excel 2010. The charts have all data set lines/styles showing in the chart and in print preview. However, when printed, some of the lines do not print although the data markers print. Under Format Chart Area, Properties, the Print Object toggle is checked. I don't see anything as an option not to print for that particular data series when I right click on the data line and go through the Format Data Series options. Any suggestions?​