Chris,
I know the feeling. My last two days were like this.

What happens if you run an MS Query against the table with the logical field? I know this is a stupid question, but are you sure the field is of type "L"?

In order to exclude data corruption, I suggest you run GENDBC() and create another DBC. Enter a couple of records and try again.

Good luck!
>Ummmm - done a validate database and reindex to no avail... OK I am tearing my hair out!! I think it's been one of those weeks - everything I have touched has gone wonky!!!