If you do not have MS Word installed and your word processor does not correctly interpret .rtf format, exported schedules or rosters may not display correctly. Word Pad, in particular, is not a full-featured word processor and will cause problems. If you do not have MS Word installed, you can use Word Online, which will allow you to view the roster in .rtf format but not edit it.
You can also export the roster in plain text format. That will enable you to open it with any word processor. However, the columns might not appear to be aligned correctly. In any case, it is a starting point and then you can re-format as necessary. You can export as plain text by choosing "Plain text" from the Format menu in the "Document Settings" pane of the Rosterizer.
You can also export the schedule as HTML by choosing the "Web page" option form the same Format menu. That will enable you to view and print the roster with a web browser in its proper formatting.
The other alternative is to use a computer with Microsoft Word installed so that you can both view and edit the roster in .rtf format, to purchase MS Word from the Microsoft web site, or obtain it from another person who has a spare copy.