>Harry,
>
>did you use any UDFs in any of the tags?
>
nope. And don't forget -
the indexing is taking place in a fresh query which is devoid of indexes at this point
different source tables yield queries with different structures but still the same problem error messages
these tables and all queries arising from them perform perfectly normally in all other contexts - including frequent use of the indexes. (they include live data being generated by my clients)

Harry