I have create a form. I have write all my business logic in my newly created class. Problem is when I am calling class method in button clicked mthod then it is giving below error


here is my class code
public void parmmethod(str _brand, str _type,
str _product,int _percentage,
date _slabstart, date _slabend,
SL_SchemeCode _schemecode,
int64 slabvaluestart,
int64 slabvalueend)
{
brand = _brand;
type = _type;
product = _product;
percentage = _percentage;
slabstart = slabvaluestart;
slabend = slabvalueend;
schemecode = _schemecode;
fromdate = _slabstart;
endate = _slabend;
this.insert_header();
this.insert_line();
}
Below is my button click method code
void clicked()
{
Args args = new Args();
RNI_Scheme2 schemeclass = new RNI_Scheme2();
schemeclass.parmmethod(RNI_Brand.valueStr(),RNI_Type.valueStr(),RNI_Product.valueStr(),
rni_percentage.value(),any2date(rni_fromdate.valueStr()),any2date(rni_enddate.valueStr()),
rni_schemecode.valueStr(),
rni_slabstart.value(),rni_slabend.value());
//super();
}