The output file that DisKeeper creates is a tab-delimited TEXT file that can be opened from any word processor or spreadsheet. To get the columns to line up, open it from your word processor, select all the text in the document (the Microsoft Word 4 keyboard shortcut is command-option-M) and then use the ruler to set your tab stops to line the columns up. An alternative would be to use a utility that can convert tabs to spaces.
NOTES: You can tell DisKeeper not to create an output file or change its “creator” by clicking on the “Scan Options” button in the Setup window and selecting “No Output File”.