I do not yet have ArcGIS 10, but the help for the tool lists a set of specific requirements of the input polygon layer that put some pretty severe limits on what will work with the tool. http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//007000000009000000.htm Are you sure that you have a polygon layer that matches all of the requirements? (I can see I will need to continue to update and use the custom coded MapBook application code I have developed, since there is no way I can make my map series conform to these limitations in any way.)
The "Calculate Adjacent Fields" tool found in the Cartography System toolbox is very limiting. It really only works with the output of the "Grid Index Features" tool in the same toolbox. It requires that all polygons be orthogonal with only 4 vertices per feature, etc.
We hope to improve these limitation in a future release. In the meantime, we've created a sample script tool that is not nearly as limiting. Please download and review the script from: