Getting error while subtracting two dates(inconsistent datatypes: expected char got date)

Getting error while subtracting two dates(inconsistent datatypes: expected
char got date)

References

Reference NO 1

http://stackoverflow.com/questions/13640064/getting-error-while-subtracting-two-datesinconsistent-datatypes-expected-char

Reference NO 2

http://stackoverflow.com/questions/18105664/expected-char-got-number

Reference NO 3

http://stackoverflow.com/questions/13512083/getting-error-that-errorsql-problems-inconsistent-datatypes-expected-number-g

Reference NO 4

http://stackoverflow.com/questions/17076495/inconsistent-datatypes-when-comparing-two-varrays-in-where-clause

Reference NO 5

http://stackoverflow.com/questions/13528869/how-to-calculate-date-after-14-days

Reference NO 6

http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:67082879150052

Reference NO 7

#EANF#

Reference NO 8

#EANF#