Most likely the task you have created is a "longterm" task (there's a checkbox to mark task as longterm). Those task are not displayed by default neither when browsing Tasks, nor in applet. To display such task you need to set the filter to "longterm" or "both".
Another option is: you assigned this task to employees, without your user on the list. Default behavior for Tasks (as well as Calendar, Tickets and PhoneCalls) is that it only displays your tasks/event etc. To see others records, click on the button "Filter: My records" and select suitable option (either certain person or everyone).
Either way, you will be able to find the task you've created.
Hope this helps,
Arek