It seems to me that the .Net program is making use of a few Oracle10g stored procedures (be it packages, procedures, functions, ..).
If you want to test the specific functionality of these stored procedures the manual of PL/SQL Developer explains in detail how you can do so. In brief you select for example a function you want to test, right-click it and click on 'Test'. I find the rest self-explanatory but if needed the manual will help you further.
Hope this helps.