Use late-binding to allow the code to run:
Dim oGraph As Object
Dim chSeries As Object
It may be that the Graph is not correctly registered on the computer. You could register it manually. I would create a Restore Point before doing this, just in case (possibly even back up the registry, but this is perhaps over cautious).
- Click the Start button, Run
"C:\Program Files\Microsoft Office\Office14\GRAPH.EXE" /REGSERVER
Re-installing Access and making sure it is up-to-date with all Windows Updates is another possibility.