Hiya iddqd,
It won't write to table. If you call CurrentUser() in your form using a calculated field, it only "calculates" for the display of that record on your form (or any "=Expression" on a form for that matter).
Make a new field/expression in your query:
FieldNameofChoice: =CurrentUser()
HTH - Junkee
P.S. This will not get it to table either, but at least you will have it "written back" on something. You can still use it for reports or manipulation etc - just like a table. It isn't necessary to get it to table. If it is life or death to get it to table, dunno.. you could run some covert append queries?