The following known issues may be encountered with XY Event layers with version 8.1:
1) When making a selection in the XY Event layer attribute table, the selection set does not remain highlighted.
2) Selecting features from the XY Event layer in the data view, opening the attribute table, and clicking the Selected button will produce an empty table grid.
3) When using the Select by Attribute dialog query records, opening the attribute table will report the correct number of records has been selected, but switching to the show selected records window returns a SQL error and an empty table grid.
These problems can occur if an XY Event layer has been created from an unregistered Access table or a table in an Access database accessed via an OLE DB connection.
Register the Access table with the geodatabase and do not use an OLE DB connection to access the table. Please refer to the ArcCatalog online help for further information on registering tables with a geodatabase.
Please be aware that registering the table will make some schema modifications to the Access database that may be inappropriate for your applications.
Click on ESRI Patches and Service Packs > ArcInfo Desktop. Under version 8.1, find ArcGIS 8.1 Service Pack 1. Follow download instructions.