How to do a "Save As" in vba code, saving my current Excel workbook with datestamp?

Most likely the path you are trying to access does not exist. It seems you are trying to save to a relative location and you do not have an file extension in that string. If you need to use relative paths you can parse the path from ActiveWorkbook.FullName

EDIT: Better syntax would also be

ActiveWorkbook.SaveAs Filename:=myFileName, FileFormat:=xlWorkbookNormal

Easiest way to use this function is to start by 'Recording a Macro'. Once you start recording, save the file to the location you want, with the name you want, and then of course set the file type, most likely 'Excel Macro Enabled Workbook' ~ 'XLSM'

Stop recording and you can start inspecting your code.

I wrote the code below which allows you to save a workbook using the path where the file was originally located, naming it as "Event [date in cell "A1"]"

Option Explicit

Sub SaveFile()

Dim fdate As Date
Dim fname As String
Dim path As String

fdate = Range("A1").Value
path = Application.ActiveWorkbook.path

If fdate > 0 Then
    fname = "Event " & fdate
    Application.ActiveWorkbook.SaveAs Filename:=path & "\" & fname, _
        FileFormat:=xlOpenXMLWorkbookMacroEnabled, CreateBackup:=False
Else
    MsgBox "Chose a date for the event", vbOKOnly
End If

End Sub

Copy the code into a new module and then write a date in cell "A1" e.g. 01-01-2016 -> assign the sub to a button and run. [Note] you need to make a save file before this script will work, because a new workbook is saved to the default autosave location!