Move to next record on Subform.

I am trying to move a subform onto the next record with:

DoCmd.GoToRecord acForm, "MaintainAssets_edit", acNext

but when I do this I get "The object 'MaintainAssets_edit' is isn't
open". I know I could easily put the controls in the subform itself
but I want the record controls at the top of the page, outside of the
subform.

Thanks for looking.

Matt