ERROR [UNKNOWN TYPE, ERRNO 404]: 
IN GET /assets/DataSheets/LA-MI14WP1.pdf
Line  in 

Trace
=====
SilverStripe\Logging\DetailedErrorFormatter->output(404, , , , )
DetailedErrorFormatter.php:55

SilverStripe\Logging\DetailedErrorFormatter->format(Array)
HTTPResponse.php:418

SilverStripe\Control\HTTPResponse->outputBody()
HTTPResponse.php:346

SilverStripe\Control\HTTPResponse->output()
index.php:24