This error is stopping my code dead in its tracks :-(

I'm programmatically creating charts when this error occurs. If I select the graph plot, right click "Format Data Series...", the error will pop up. Click OK
and then the standard "Format Data Series" window displays like normal. Is there a way to, uh, clear out the register or whatever that keeps tabs on this
setting?

Here's where the code is breaking:
....
chartAvgCalls.Axes(xlCategory).Select
Selection.TickLabels.AutoScaleFont = True
With Selection.TickLabels.Font
.Name = "Arial"
.FontStyle = "Bold" '<-- this is where the error occurs
.Size = 10
End With
....

Ideas?
Toby Erkson
Oregon, USA