ERROR: heapgettup: failed ReadBuffer

I put  360000+ rows in a table , and now any select , update , analyze 
... command fail.
the log shows  "ERROR: heapgettup: failed ReadBuffer",
but any INSERT sql command success.


the table schema is

       row        |              type               |     modifiers
---------------+-----------------------------+----------
 test_id       | integer                     | not null
 snapshot      | timestamp without time zone |
 ip_client     | inet                        |
 ip_server     | inet                        |
 conn_time     | integer                     |
 response_time | integer                     |
 response_head | character varying           |
Check constraints:
    "invalid_conn_time" CHECK (conn_time >= 0)
    "invalid_resp_time" CHECK (response_time >= 0)


I didn't create any index,
any one know why or suggestion to save the un-readable database?

or anything I mis-configuration ??

Thanks for your help.

June-Yen