beforecolupdate & error 7011

hi,

I am unable to add records to my database through datagrid unless I populate some fields. I don't understand this at all. I have to populate the last field,which is text OR I have to populate two other fields that are also text.
This seems very strange to me.
I tried putting code in the beforecolupate,change,beforeupdate events,onaddnew, and NOTHING is working. I am doing something wrong. Here's what I have in my
beforeupdate event :
if datgrid1.column = 1 then
If DataGrid1.Columns(1).Text = Null Then
datagrid1.text = " "
endif
End If
I also have tried setting up a value in CHANGE event to get the value of datagrid1.text , which also seems to not work. I don't even see my displays most of the time.

HELP! ! ! !
thanks,
Maggie