Adding calculations to table with form field and macro?

Hi

I have little difficulties to start.
I have tried this kind (and many kinds of) macro but I have used to have 
help of macrorecorder, so ....

Sub d100
Dim vField, vForm as object
vForm = DataBaseForm.getByName("txtSex") 'Form is open and there is 
textfield named txtSex which is aiming to tablecolumn 'Sex'
Randomize
iVar =  Int((100*Rnd)+1)  ' number from 1 to 100
vField.value  = iVar 'I'm trying to add value to field and to table without 
success:)

Can you help a bit
with Regards
Hoo