Problem: Why can't I successfully join OLE DB tables to other data sources?
In some cases, although the OLE DB table will open correctly in an ArcMap table window, join operations using this table will fail.
One of the most likely causes for this is an invalid field in the table; either there is a space or invalid character in the field name, or the field name is too long.
Solution or Workaround
Make sure the fields have valid characters (no blank spaces) and meet ODBC field name length requirements (31 characters).