Hi Laxmikanth,
Some more info would be helpful. Such as posting a image of your program, which version of labview, platform etc.
that being said if you are literally typing in the filepath that is the most likely source for the error. Is there a browse button visible to the right of the filepath control? If not try right clicking and under the visible menu make sure the browse button is selected. Then click on the browse button and find/select your disk file. Now run the program and see if you get the same error.
Cheers,
--Russ