The report you have just created is a reusable part and requires information from your BusinessExpenseView part to run properly:
If you want to test the report from its own Composition Editor, you will need to provide test data. A convenient way of doing this is to override the instance method finalInitialize and set values for the host variable and the ordered collection at that point.
finalInitialize "Provide information to the report for testing" ((self subpartNamed: 'Multiple Row Query1') valueOfAttributeNamed: 'name' selector: #'IS_name') == nil ifTrue: [(self subpartNamed: 'Multiple Row Query1') valueOfAttributeNamed: 'name' selector: #'IS_name' ifAbsent: [] put: 'Graham']. (self subpartNamed: 'Expenses') value: (Array with: (BusinessExpense new date: (Date today); reason: 'Sales call'; airfare: 200; room: 100; meals: 50; misc: 10; yourself) with: (BusinessExpense new date: ((Date today) addDays: 1); reason: 'Sales call'; airfare: 0; room: 100; meals: 75; misc: 0; yourself) with: (BusinessExpense new date: ((Date today) addDays: 2); reason: 'Sales call'; airfare: 0; room: 100; meals: 65; misc: 5; yourself)).
It should look similar to the following:
Your report will run in a report viewer that is embedded in a report tester window. From the Report menu in this window, you can select Preview to display a printer-formatted preview of the report or Print to print the report.