Problems with using F#'s Event Trigger functions in an async block when running on Android?

Hi!

I keep getting an Android.Util.AndroidRuntimeException when running my program on my Android phone. I am trying to run a simple program which basically runs a loop inside an async block when a button is pressed. The loop is supposed to use the Event.Trigger function each iteration to update a textbox with the current iteration. And it is when Event.Trigger is used that i get the exception.

In AsyncTest.fs:

let runAsyncLoop (ev:Event<string>) =
    ev.Trigger "Pre async"    //This causes no exception
    async {
        for i in [1..10] do
            ev.Trigger ("Iteration: " + i.ToString())    //Error here
            do! Async.Sleep 1000
}

let runAll (ev:Event<string>) = 
    Async.Start (runAsyncLoop ev)
    "Async started!"

In MainAcitivity.fs:

let textBox = this.FindViewById<TextView>(Resource_Id.asyncStatus)
let updateTextBox s = textBox.Text <- sprintf "%s" s
let ev = new Event<string>()
ev.Publish.Add(updateTextBox)
let toggle = this.FindViewById<ToggleButton>(Resource_Id.asyncToggle)

toggle.Click.Add (fun _ ->
    if toggle.Checked 
        then    let s = runAll ev
                textBox.Text <- sprintf "%s" s
        else    cancelSource.Cancel()
)

The whole 'trigger inside async' works fine when just running it on my pc so I thought there might be some known problems with this combination on Android. Or maybe it is just my program that fails. Either way I hope you will be able to help

Cheers!