>>>>>Has anyone heard of a fault like this before?
>>
>>Check the privileges on all your tables and indexes. We had a major support headache that turned into a cdx somehow losing privileges when copied between servers by the customer. Everything worked fine when logged in as admin/owner, otherwise index error.
>
>The answer is dont use c:\ for string tables use c:\anythingelse and you are ok

The general recommendation is to not use the c: drive at all - it doesn't belong to you anyway, it's appropriated by some thugs from Redmond. Also don't use any location which they mark as special, and you'll live longer. Or get more mileage from your nerves.