操作Oracle数据库实现上传图片到Blob类型的字段出现的问题

通过使用OleDb操作Oracle数据库，成功实现图片上传到Blob类型的字段，但有时会发生ORA-01036错误的问题，经查询是错误提示为illegal variable name/number，不知道有谁能详细解释illegal variable name/number的意思
Oracle Data Provider for .NET
Hi
I am using ODP.NET (Oracle Data Provider for .NET) in my asp.net application.
I have a table in my oracle database called "equipmentgroup". When the page loads for the first time i retrieve all the records from the table to a dataset and save it to viewstate. Later on any addition or modification is done in the dataset only in disconnected mode. Finally,when user clicks update i call this function "update" which should do a batch update but instead it gives the following error :
"ORA-01036: illegal variable name/number "
private void update()
{
OracleParameter workParam;
OracleConnection cnn = new OracleConnection("Data Source=NEELESHR;User Id=tmse; Password=tmse;");
string sql = "INSERT INTO EquipmentGroup (Code, Description, LifeTime, PriamryLife, Grading, Inflator, ExtensionRate, MaintenanceFee) VALUES (:Code, :Description, :LifeTime, :PriamryLife, :Grading, :Inflator, :ExtensionRate, :MaintenanceFee)";
OracleCommand cmd = new OracleCommand(sql,cnn);
cmd.CommandType = CommandType.Text;
OracleDataAdapter da = new OracleDataAdapter();
da.InsertCommand = cmd;
workParam = da.InsertCommand.Parameters.Add("Code",OracleType.Char,10,"Code");
workParam.SourceVersion = DataRowVersion.Current;
workParam = da.InsertCommand.Parameters.Add("Description",OracleType.VarChar,50,"Description");
workParam.SourceVersion = DataRowVersion.Current;
workParam = da.InsertCommand.Parameters.Add("LifeTime",OracleType.Number);