FastPath protocol SQLException

Dear All,

i am trying to insert image in postgres 7.0 by using following code:
i am getting FastPath protocol error : Z
Could any one reply earliest...?
Any feasible solution ?

PreparedStatement stmnt =conn.prepareStatement("insert into
grms_photogallary (user_id,oid) values (?,?)");
// Set parameters
String userId="soms";
stmnt.setString(1, userId);
File file = new File("/jigsaw/jigsaw/www/easilogo.gif");
InputStream photoIn=new FileInputStream(file);

int size=photoIn.available();

String str="";
for(int i=0;i<size;i++)
{
str+=(char)photoIn.read();
}
byte blobData[]=str.getBytes();
stmnt.setBytes(2,blobData);

Thanks in advance
Som