ArcPad 10 requires ArcGIS 9.3 or higher. Please note, The ArcPad 10 Data Manager toolbar will only be installed with ArcGIS 10. For 9.3 and 9.3.1 versions of ArcGIS, the 8.0 version of the toolbar will automatically be installed and will not be able to take advantage of any new functionality that was introduced at version 10.