What's got wrong with the table?

[Samir Guermach]

Hi
I'm using mysql version 3.21.29a-gamma. After updating the blob column in a table "update
test_table set image_blob=? where image_name=?", I can no more read the entries int the
table.
the table is defined as follows :image_name varchar(50) primary key, status integer,
image_blob longblob.
"select count(*) from test_table" returns 1, but select * from test_table returns empty
set, and 
insert into test_table values('myimage', 2,null) returns error 1062: Duplicate entry
'myimage' for key 1




thanks