Stupid Error

this is a very strange error it happends before but I still dont know the problem :(
my mysql is working fine
heres the error and plz help me to fix it :(

Code:

MySql.Data.MySqlClient.MySqlException: Connection unexpectedly terminated ---> System.IndexOutOfRangeException: Probable I/O race condition detected while copying memory. The I/O package is not thread safe by default. In multithreaded applications, a stream must be accessed in a thread-safe way, such as a thread-safe wrapper returned by TextReader's or TextWriter's Synchronized methods. This also applies to classes like StreamWriter and StreamReader.
   at System.Buffer.InternalBlockCopy(Array src, Int32 srcOffset, Array dst, Int32 dstOffset, Int32 count)
   at System.IO.BufferedStream.Read(Byte[] array, Int32 offset, Int32 count)
   at MySql.Data.MySqlClient.PacketReader.Read(Byte[]& buffer, Int64 pos, Int64 len)
   --- End of inner exception stack trace ---
   at MySql.Data.MySqlClient.PacketReader.Read(Byte[]& buffer, Int64 pos, Int64 len)
   at MySql.Data.MySqlClient.PacketReader.Skip(Int64 count)
   at MySql.Data.MySqlClient.PacketReader.OpenPacket()
   at MySql.Data.MySqlClient.NativeDriver.ReadResult(Int64& affectedRows, Int64& lastInsertId)
   at MySql.Data.MySqlClient.CommandResult.ReadNextResult(Boolean isFirst)
   at MySql.Data.MySqlClient.CommandResult..ctor(Driver d, Boolean isBinary)
   at MySql.Data.MySqlClient.NativeDriver.SendQuery(Byte[] bytes, Int32 length, Boolean consume)
   at MySql.Data.MySqlClient.MySqlCommand.GetNextResultSet(MySqlDataReader reader)
   at MySql.Data.MySqlClient.MySqlCommand.Consume()
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
   at COServer_Project.DataBase.SaveChar(Character Charr)

Code:

System.InvalidOperationException: Connection must be valid and open
   at MySql.Data.MySqlClient.MySqlCommand.CheckState()
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
   at COServer_Project.DataBase.SaveChar(Character Charr)

whene these errors come out I need to restartr server every item that player got or level everything disappear and server start to lag so mutch that you cant play ! so what is the problem ?