visual basic 2010 coding related question

hi everyone i am making a program on visual basic 2010 and i need some quick help, part of my objective is to calculate the tax, i am trying to calculate the TAX so this is part of my code and this is the only part which gives me errors:

Code:

---

Const decNetAdultTicketSales_TAX_RATE As Decimal = 0.2D

 ' Calculate the Net Adult Ticket Sales

            decNetAdultTicketSales_TAX_RATE = decGrossAdultTicketSales *
                                                      decNetAdultTicketSales_TAX_RATE
            lblNetAdultTicketSales = decNetAdultTicketSales_TAX_RATE.ToString("c")

---

my problem is i am getting these 2 erroes in the lines u see on my code:
1. Constant cannot be target of an assignment
2. value of type 'string' cannot be converted to 'System.windows.forms.Lebel'.

try this:

vb Code:

Const decNetAdultTicketSales_TAX_RATE As Decimal = 0.2D
 
' Calculate the Net Adult Ticket Sales
 
lblNetAdultTicketSales.text = (decGrossAdultTicketSales + (decGrossAdultTicketSales * decNetAdultTicketSales_TAX_RATE
)).ToString("c")

thanks for help