From the information, i understand that u have written a
function and trying to pass values to that funciton..

Here is an example:
I have created a function called Add and taken two arguments
" a" and "b". And called that function by passing the values
as 2 and 3

Function Add(a,b)
c=a+b
msgbox c
end function

add 2,3

In the above answer (a,b) are the arguments not parameters. 
And we called as arguments in functions.

We will defeinitely pass the parameters to Function

Try with this Example

First parameterize the Agent name with invalid data like sun
Dialog("Login").Einedit("AgentName").Set datatable.Value
("Agent")
Call the function
Function Login(Sunny)
Dialog("Login").Einedit("AgentName").Set datatable.Value
("Agent1")
End Function