problem in field symbols in ecc6.0

i have the following code written in 4.6 version now i am executing the old report in 6.0 but i am facing with some unicode error.

FIELD-SYMBOLS:

<line_of_bs_table> LIKE tbl1024,

READ TABLE bs_table INDEX row_bst ASSIGNING <line_of_bs_table> .

buffer_bsbuffer_ptr(aux) = <line_of_bs_table> >col_bst.

tb1024 is standard sap structure for storing buffer contents

i have the following error in ecc 6.0

structure type '<line_of_bs_table> >+col_bst' does not start with a charecter type field in unicode programs in such cases

offset/ length declarations are not allowed.

can any one tell how can a field symbol structure is changed to charecter type.