How I can use FreerTos section to use web server, to make task statistics?
Hmm. Not quite sure what you are asking. If you want to display task statistics on a WEB page then take a look at any of the WEB server demos. There are demonstrations how to do this in both the uIP and lwIP versions.
If you just want to get a buffer filled with the task states then take a look the function vTaskList() in tasks.c. This is the function used by the WEB server demos to generate the data.