'Unable to load the requested file' error

[eluser]schidy[/eluser]
How do you call it, where is the function stored and does the function contain filesystem functions?
----------
I call it from my main controller class to generate a piece of dynamically updated html code.
And then i insert this code in to the main html file.

parser class and parse method are in code igniter libraries folder.

The error is generated from code igniter, Loader->_ci_load(..) method. I could not understand this method clearly.