Naveen,
I don't see what you are using as the sampling rate. This will be a determining factor on where the fundamental component of the sampled waveform will be located in the FFT window.
Check the CCS context help for details on these properties (the FFT Magnitude topic points to the Graph Properties Descriptions). It says there the sampling rate is rounded to the nearest power of two, therefore it may be a reason why the frequency is slightly drifted (although I think this difference would be very minimal).
Some additional interesting details about FFTs can be found at this page.
Hope this helps,
Rafael
(edit) removed leftover information from my edits.