Problem: Pasting point features may cause ArcMap to fail
This problem is addressed in ArcGIS 8.1 Service Pack 1. See Related Information section to download this pack.
Pasting point features that are not z-aware into a z-aware feature class (stores elevation values) may cause ArcMap to fail.
Solution or Workaround
Create a new feature in the target layer using the Create New Feature edit task. You can ensure coincidence with the source feature by snapping to it.