Earlier, I encountered this bug, but could not create a small program to reproduce the behaviour.
Now, I've found the problem:

SET MULTILOCKS ON
CREATE DATABASE Dat
CREATE TABLE X (Dummy I)
CREATE SQL VIEW Vw_test AS SELECT * FROM Dat!X 

Thisview="vw_test"
DBSetProp(ThisView,"View","SendUpdates",.T.)
DBSetProp(ThisView,"View","BatchUpdateCount",1)
DBSetProp(ThisView,"View","CompareMemo",.T.)
DBSetProp(ThisView,"View","FetchAsNeeded",.F.)
DBSetProp(ThisView,"View","FetchMemo",.T.)
DBSetProp(ThisView,"View","FetchSize",100)
DBSetProp(ThisView,"View","MaxRecords",-1)
DBSetProp(ThisView,"View","Prepared",.F.)
DBSetProp(ThisView,"View","UpdateType",1)
DBSetProp(ThisView,"View","UseMemoSize",255)
DBSetProp(ThisView,"View","Tables","dat!x")
DBSetProp(ThisView,"View","WhereType",3)

DBSetProp(ThisView+".dummy","Field","DataType","I")
DBSetProp(ThisView+".dummy","Field","UpdateName","dat!x.dummy")
DBSetProp(ThisView+".dummy","Field","KeyField",.T.)
DBSetProp(ThisView+".dummy","Field","Updatable",.T.)


USE vw_test
CURSORSETPROP("Buffering", 3)
INSERT INTO vw_test VALUES (2)
INDEX ON Dummy TAG Dummy ADDI

BEGIN TRANSACTION
	=TABLEUPDATE(2,.T.)
END TRANSACTION
=REQUERY() && If you omit this statment, the error does not occur.

INDEX ON Dummy TAG Dummy ADDI
REPLACE Dummy WITH 1

BEGIN TRANSACTION
	=TABLEUPDATE(2,.T.)
END TRANSACTION

It will error on the second BEGIN TRANSACTION with "Table vw_test has one or more structual indexes open..." (error 1548), while I did not create a non structual index at all. Further, the error does only occur when you do a REQUERY() after a first update.

You can workarround the issue to omit the second INDEX ON statment, but this issue is definately a BUG.

Walter,