Problem writing image(Blob) to file

Question

Hi ,
I'm trying to write image to file. The Image(26KB) is stored in database as BLOB. I have to change this to CLOB because when I try to write to file its writing all junk data. So I converted BLOB to CLOB then I try to write its giving me error.
ORA-21560 :argument string is null, invalid, or out of range
Cause: The argument is expecting a non-null, valid value but the argument value passed in is null, invalid, or out of range. Examples include when the LOB/FILE positional or size argument has a value outside the range 1 through (4GB - 1), or when an invalid open mode is used to open a file, etc.
Action: Check your program and correct the caller of the routine to not pass a null, invalid or out-of-range argument value.
The size of IMAGE after coverting to CLOB is 21102 bytes which is between the range.
Here is how my code looks like:
DECLARE
f UTL_FILE.file_type;
l_blob_len INTEGER;
buffer VARCHAR2 (32767);
buffer_size CONSTANT BINARY_INTEGER := 32767;
amount BINARY_INTEGER;
offset NUMBER (38);
l_blob BLOB;
l_clob CLOB := 'x';
l_dest_offsset INTEGER := 1;
l_src_offsset INTEGER := 1;
l_lang_context INTEGER := DBMS_LOB.default_lang_ctx;
l_warning INTEGER;
BEGIN
SELECT blobdata
INTO l_blob
FROM lob_table ip
WHERE ip.id = 2;
DBMS_LOB.converttoclob (dest_lob => l_clob,
src_blob => l_blob,
amount => DBMS_LOB.lobmaxsize,
dest_offset => l_dest_offsset,
src_offset => l_src_offsset,
blob_csid => DBMS_LOB.default_csid,
lang_context => l_lang_context,
warning => l_warning);
amount := buffer_size;
offset := 1;
f := UTL_FILE.fopen ('IN_FILE_LOC', 'something.doc', 'w');
WHILE amount >= buffer_size
LOOP
DBMS_OUTPUT.put_line ('buffer_size');
DBMS_LOB.READ (l_clob,
amount,
offset,
buffer);
UTL_FILE.PUT (f, buffer);
UTL_FILE.FFLUSH (f);
END LOOP;
UTL_FILE.fclose (f);
END;
Please tell me what did I do wrong.

Answer 1

Try this posts
http://www.oracle-base.com/articles/9i/ExportBlob9i.php
http://download.oracle.com/docs/cd/B10500_01/appdev.920/a96591/adl06faq.htm