I'm getting the error message Unrecognized Service Parameter Block during FbBackup.Execute in my c# code.

I'm using code found in the FireBird online documentation.

                myConnectionString =
                    "User=SYSDBA;" +
                    "Password=masterkey;" +
                    "Database=" + databaseFileTextbox.Text + ";" +
                    "DataSource=localhost;" +
                    "Port=3050;" +
                    "Dialect=3;" +
                    "Charset=NONE;" +
                    "Role=;" +
                    "Connection lifetime=15;" +
                    "Pooling=true;" +
                    "MinPoolSize=0;" +
                    "MaxPoolSize=50;" +
                    "Packet Size=8192;" +
                    "ServerType=0";

                FirebirdSql.Data.Services.FbBackupFile file = new FirebirdSql.Data.Services.FbBackupFile(newDatabaseFileTextbox.Text.Remove(databaseFileTextbox.Text.Length - 3) + "FBK", 2048);
                FirebirdSql.Data.Services.FbBackup backupSvc = new FirebirdSql.Data.Services.FbBackup();

                backupSvc.ConnectionString = myConnectionString;
                backupSvc.BackupFiles.Add(file);
                backupSvc.Verbose = true;
                backupSvc.Options = FirebirdSql.Data.Services.FbBackupFlags.IgnoreLimbo;
                backupSvc.ServiceOutput += (s, ev) => LogMessageToTextBox(ev.Message);
               
                backupSvc.Execute();

any hint?

fede