Hi Praveen,
Your XSD seems to be right.
Right we can figure out if you configuration fits with your file, regarding the help.sap documentation:
If you made an entry for NameA.fieldFixedLengths, the length of the separator is not added to this length.
Have you taken into account that you don't have to count the tab separator in your fieldFixedLenghts parameter?
You must make an entry for at least NameA.fieldFixedLengths or NameA.fieldSeparator.
If you have a fieldSeparator, why are you using fieldFixedLenghts?
Finally, without count the tab character, are you really sure all records in the file have the length that you are setting in FCC?.
Regards.