insert action is error

[philips philips]

i find the errors that happened in the insert action .
table's definition :

s_d_id int(4) not null
s_d_amount_unit varchar(10) not null
s_d_lanuage varchar(20)
...........................

when i inserted value into this table , usually it success. but sometime it happened a error like this .
insert into table value(11,"","")
usually it will report a error , but
in the database ,sometimes,
the value was inserted successful.

the case is happened randomly.
maybe when the server was restarted or something else happened ,the data was ignored checking .
i dont know why .
maybe it is a bug in mysql database .