This function retrieves a user-defined element number based on a specified internal element index within a particular element set.
GetSetElement (string DatabaseName, string SetName, int ElementIndex)
DatabaseName (character string). The full path name to the relevant database.
SetName (character string). The full name of the relevant set.
ElementIndex (integer). The element index within the relevant set.
-9999990 (if the element number is out of bounds)
-9999998 (if the specified database is invalid)
-9999999 (if the specified set name is invalid)