000852 : Cannot add field <value> to <value>
Description
There was an unexpected error during the Add Field process. This can happen when a file is in use by another program, the file is read-only, or the disk is full.
Solution
Check whether the table is locked by another user or is read-only. You can try using different output files. If that doesn't work, try closing ArcMap and/or ArcCatalog and run the tool again. If that doesn't work, call ESRI Technical Support.
11/18/2010