I managed to compile a workbench version of ec and run "ec -bench" under the
debugger.  When I ran the external command "echo hi", I got a precondition
violation.  Here's what I found as I explored:

1. {EB_EXTERNAL_OUTPUT_TOOL}.process_text_block calls `output_text.append_text'
   and passes it a Void reference, which violates the precondition of
   `append_text'.

2. The Void is produced by a call to

      source_encoding.convert_to (destination_encoding, str)

   Source encoding is ISO8859-1.
   Destination encoding is UTF-16.

3. {ENCODING}.convert_to is fails to do the conversion and is correctly
   setting `last_conversion_successful' to False, but the caller is not
   checking this boolean.

4. {ENCODING}.convert_to calls {ENCODING}.is_valid, which returns False.

5. {ENCODING_IMP}.is_code_page_valid is called with argument "UTF-16"
   and it returns False.  This routine calls `is_codeset_convertable,
   which just calls iconv_open, passing pointers to "UTF-16" as the "to"
   and "from" codesets.

So perhaps I don't have UTF-16 available on this Solaris 10 Update 1
host, with all recent patches applied.  

Let me know if I can help further.