Urgent help!!!!... SELECTBLOB ERROR...PB 6.5

Hi:

I am using PowerBuilder 6.5 with Oracle 11G. I get an error on SELECTBLOB from a table.

Blob    lblb_data

/*end of declaration*/

SELECTBLOB BLOBCOLUMN

INTO :lblb_data

FROM   TBL

WHERE  ORDERNO = :as_order_no

AND BLOBCOLUMN is not null;

Please help!!!!.