Update or CancelUpdate without Addnew or Edit

[dumdum2]

I keep getting this message and I can't seem to figure out why.....

I have a form where the user enters a filename. A command button is pushed and another form opens. The code behind the command button is:

Dim stDocName As String

stDocName = "external_main"
DoCmd.OpenForm stDocName
DoCmd.GoToRecord , , acNewRec
Forms![external_main]![filename] = Forms![enter image name]![filename]
DoCmd.RunCommand acCmdSaveRecord

The filename gets carried over ok, but after I enter the data in the next field (a title field), I get the message mentioned above. If I skip the next field and enter data in other fields on the form and then come back to the title field, I don't get the error message....

Why do I get this message if there is a new record added?

Thanks!