Thanks for the the screenshots.
Well, it should work equally fine on both platforms/OS. I suspect it might be due to missing fonts issue. Please make sure all the fonts (especially used in your Excel spreadsheet(s)) are installed on your Linux server too as you already have on Windows. Your Linux machine does not have all the required fonts (used in the workbook) that are needed for rendering. Please collect all the required fonts from your Windows machine which is working and place them in some directory on Linux machine. Suppose, you have placed the fonts in /usr/temp/myFonts directory, then set the fonts folder as below.
//fontFolder = "C:/temp/myFonts";//This is for Windows <<<
Please note, you must execute this code before you execute any other Aspose.Cells code. For more information, please see these articles in the section:
Hope, this helps a bit.