sqlldr error

when I try from the Command Line The following sqlldr command

sqlldr scott/tiger@orcl D:\NEW\\ADCOLNA _PT_GRID

it gives me following errors
sql*loader error 500 unable to open file
sql*loader eroor 553 file not found
sql*loader error 509 the system can not find specified file.



how u have solved the problem?

can you guide...