> Is what I'm doing fundamentally wrong? (i.e. should I only
> be using SQLWhereItems?)

This is hard to answer without greater detail. My instinctive
response would be to say: "Yes use the built in features", but
I know from experience that these are not always the simplest
or more appropriate for every situation.

> Sorry for the windy description, but params/preparing is
> something that I really should be understanding now, but it's
> still a little arcane...

I hope my other posting helped a little bit. What I suggest:

If you have moved to FB v1.5 then go into its "firebird.conf"
configuration file (in the installation root) and set:

OldParameterOrdering = 1

Keep this setting until IBO has been updated to detect FB 1.5
and its new more obvious parameter ordering. This will at
least allow IBO to automate your parameters as it always has.

If your AV is happening due to some other situation (other
than moving to FB 1.5) then it may help if you can post the
callstack from when the AV has occured - not to mention the
FULL SQL being sent to the server (perhaps look at the SQL
Monitor to be sure).

--
Geoff Worboys
Telesis Computing