Automation Error running Spatial Analyst operations

[StefanosKargas]

I am using ArcMaps VBA
I am using ISurfaceOp.Visibility and IDistanceOp.CostDistance
and I get Automation Error for both.
My data is correct. It used to work.
Suddenly it doesn't work
What could this mean

[JeffreySwain]

If you have transitioned to 10 then the problem is the VBA.  You need an additional license for the process. There is more information for developers here.

[StefanosKargas]

If you have transitioned to 10 then the problem is the VBA.  You need an additional license for the process. There is more information for developers here.

I use ArcGIS v9.3.1