if(typ='A') then
INSERT INTO emp(empno, NAME, typ, rate, hrs)
VALUES (@empno, @NAME, @typ, @rate, @hrs);
FETCH Cur INTO @empno, @NAME, @typ, @rate, @hrs;

elseif(typ='B') then
INSERT INTO emp(empno, NAME, typ, ans, comm)
VALUES (@empno, @NAME, @typ, @ans, @comm);
FETCH Cur INTO @empno, @NAME, @typ, @ans, @comm;
end if;

error//The data types of corresponding columns are not compatible in a fullselect that includes a set operator or in the multiple rows of a VALUES clause of an INSERT or fullselect.

how and where will i cast values? in what statements?

Could you please post the complete error message, table definitions, cursor declarations, and some information to your DB2 environment?

Make sure that the datatypes of e.g. variable @NAME and column NAME match.
Just check the column datatypes in the catalog.

(For example, column empno might be a CHAR(4) while variable @empno might be an INTEGER; those datatypes are incompatible.)