IronCow Task Deletion Permissions Problem

I'm using the IronCow managed API for RememberTheMilk (http://ironcow.codeplex.com/) and I'm trying to remove tasks using my program. I've already logged in and downloaded the tasks list, but when I later try to remove one I get the following exception:

[IronCow.RtmException] = {"User not logged in / Insufficient permissions"}

I'm removing tasks using this code (rtm is my logged in RTM object, myTask is the Task object I'm looking to delete)

TaskListCollection tlc = rtm.TaskLists;

foreach (TaskList list in tlc)
{ 
    TaskListTaskCollection taskListsTasks = list.Tasks;
    foreach (Task task in taskListTasks)
    {
  开发者_运维问答      if (!(task.IsDeleted || task.IsCompleted) && task.Name == myTask.Name)
        {
            list.Tasks.Remove(task);
        }
    }
}

the line it errors on is list.Tasks.Remove

Discovered it was a permissions problem due to permissions being stored from an old version of the app that didn't need to delete