create table blobz (zin blob sub_type 1);
commit;
/* insert stuff - or not... */

The following query:

  select * from blobz where zin like cast(cast('woord' as char(32766)) as blob sub_type 1) || '!'

works, and returns a set which may or may not be empty, depending on what's in the table.

Now we add one more char:

  select * from blobz where zin like cast(cast('woord' as char(32767)) as blob sub_type 1) || '!'

and we get: 335544321 - arithmetic exception, numeric overflow, or string truncation
(in 2.5, the following is added: blob truncation when converting to a string: length limit exceeded)

This happens with LIKE, STARTING and CONTAINING.