SDMY,
Again there is a syntax error in your code.
Instead of writing
FILEHANDLER:=UTL_FILE.FOPEN(L_DIR||abc.sql,'W');
You are supposed to write
FILEHANDLER:=UTL_FILE.FOPEN(L_DIR,'abc.sql','W');
Also please ensure that directory 'c:/sample' exist for the utl_file parmaeter in your DB...