Load Flat-File - Error Command failed *COL(5); column index is out of range

Gurus ,

While I am loading the flat-file with mapping below in the transformation file ,i get the error

"Error Command failed *COL(5); column index is out of range"

All the fieds are CHARECTERISTIC and am using data manager package "import master data from FILE SERVICE"

I get error if I leave the all the columns as BLANK values (ID coumn is filled)

A=*COL(1)

B=*COL(2)

.

.

E=*COL(5)

If I fill the values in all the columns then the data gets loaded.

So the question ,is all the fields mandatory to be populated ,as there are cases when the fields will be left blank

Thanks