Oracle Database Discussions

I created a table in oracle database(10g) as following:
CREATE TABLE
SEAL_IMAGE (
SEAL_OF_NAME VARCHAR2(80) PRIMARY KEY,
DESIGNATION VARCHAR2(100),
SEAL_OF_IMAGE blob,
DEFAULT_FLAG VARCHAR2(1) DEFAULT 'N',
DELETEd_FLAG VARCHAR2(1) DEFAULT 'N');
But, when I tried to update the blob column in PowerBuilder(v10.5), I got error ORA-00911: invalid character. Other tables with blob column can update correctly. I dropped the table, and used the following to recreate the table:
CREATE TABLE
SEAL_IMAGE (
NAME VARCHAR2(80) PRIMARY KEY,
DESIGNATION VARCHAR2(100),
IMAGE blob,
DEFAULT_FLAG VARCHAR2(1) DEFAULT 'N',
DELETED_FLAG VARCHAR2(1) DEFAULT 'N');
The problem insists.

I don't know why others can be updated except this one. So I created another table with blob column as following:
CREATE TABLE
SIGNATURE (
id VARCHAR2(5),
IMAGE blob);
For this table, the blob column can be updated successfully.

Can anyone show me what's wrong in the first table definition?

Thanks.