you have mentioned d inside the query string. Which means it will take it as d and not as its value.
you should use something like this
strSql = "Isert into table1 (betty_inv_daily) values (" & CStr(d) + ")"
I am not very sure of the
VB syntax..quite sometime since used
VB (CStr is convert to string if i am not wrong).
Regards
Ganesh