A 3D shapefile indicates Z or M values in the Shape field of the attribute table, for example PolylineM and PolylineZ.
If the theme is a multi-point shapefile, convert it to a point shapefile. ArcView does not come with this functionality; however, it is possible to use Avenue to accomplish this task. It is possible to create code or download a script from the ArcScripts Web site (see Related Information).
If the above does not solve this problem, use Windows Explorer to check and change the shapefile's permissions.
A. Start Windows Explorer. B. Navigate to the shapefile C. Select the files associated with the shapefile (SHP, DBF, SHX, PRJ, SBN, SBX). D. Right-click and select Properties. E. Uncheck the Read-Only option. F. Click Apply and OK.