SQL Fetch problem with BLOB

I'm trying to select all records in a file with BLOB's and transfer them
via FTP to an imaging server. This previously worked fine but we are
receiving a SQLSTT

428A1-Unable to access a file referenced by a file reference variable.

Code snips looks like this:

D Blob s SQLTYPE(BLOB_FILE)

EXEC SQL Select rid, dwLineNo, dwimg01
from dwImages
where dwsent = '1900-01-01 00:00:00';

EXEC SQL Fetch Next from C1 into :rid, :DwLineNo, :Blob;

Error in joblog
Message ID . . . . . . : SQL0452 Severity . . . . . . . : 30

Message type . . . . . : Diagnostic

Date sent . . . . . . : 04/08/19 Time sent . . . . . . :
11:33:48


Message . . . . : Unable to access a file that is referred to by a file

reference variable.

Cause . . . . . : The file referred to by the file reference variable
(host
variable 3) could not be accessed because of reason code 2. The reason
codes
and their meanings are:

-- 2 - The length of the file name is greater than the maximum allowed

length.

-- If the reason code is 2, correct the file name and then try the request
again.

If I look at the data the image file names look ok.

Thanks