I've used this scheme succesfully and w/o error w/IBOTable,
but now with IBOQuery I'm getting 'Dataset not in edit or insert
mode':

BlobStrmSave: TStream;
{Ed: TMemo}

if IBOquery.Active then
begin
if IBOquery.State <> dsEdit then
IBOquery.Edit;
if IBOquery.State = dsEdit then
begin
BlobStrmSave := IBOquery.CreateBlobStream(IBOquery.FieldByName
('NOTES'), bmWrite);
try
Ed.Lines.SaveToStream(BlobStrmSave);
IBOquery.Post;
Ed.Modified := False;
finally
// this call returns 'Dataset not in edit or insert mode' ???
FreeAndNil(BlobStrmSave);
end;
end;
end;