According to my web searches, you need to increase the BLOB SIZE parameter in the BDE administrator:
- http://www.borlandtalk.com/blobstream-limited-to-32768-bytes-vt34635.html
- http://www.delphigroups.info/2/63/235340.html
The first of these threads suggests an alternative approach of setting RequestLive of the TQuery to be True.
The second thread dates from 1902 which would appear to be a rare sighting in the wild of the Y2K bug!