, erro ao utilizar o ExecuteNonQuery

Pessoal no ExecuteNonQuery ocorre uma exceção nao sei pq, alguem poderia me ajudar? Minha classe herda de outra os objetos command e conexao.Public Sub AlterarPerfilUsuario(ByVal cod_perfil_per As Int32, ByVal des_perfil_per As String) Try Me.conexao.Open() Me.sqlTran = Me.conexao.BeginTransaction Me.command.CommandText = "usp_fmu_AlterarPerfilUsuario" Me.command.Parameters.Add("@cod_perfil_per", SqlDbType.Int).Value = cod_perfil_per 'Me.command.Parameters("@cod_perfil_per").Direction = ParameterDirection.Input Me.command.Parameters.Add("@des_perfil_per", SqlDbType.NChar).Value = des_perfil_per 'Me.command.Parameters("@des_perfil_per").Direction = ParameterDirection.Input Me.command.Connection = Me.conexao Me.command.ExecuteNonQuery() Me.sqlTran.Commit() Catch ex As Exception Me.sqlTran.Rollback() Finally Me.conexao.Close() Me.command.Dispose() End Try End Sub