formlib unable to recognise instance of object textbox added during runtime

Hi all,
I have a program that displays some work roster,
added a textbox in part of my code

AddTextBox(PanelC,"textbox46",0,675,220,15,ddd & "" &ddmm)

i have a formlib object which i want to use to change the font of the textbox

flb.New1("Form1",B4PObject(1)) which i initialise earlier on

after adding the text box i call this code
flb.ChangeFont("textbox46","Courier New")

but it returns me error during runtime object reference not set to instance of an object.
any help?

It works fine with me