>Thought you might like to see the code I am using
>
>//Clear previously placed controls
> foreach (Control c in this.Controls)
> {
> if ( (string)c.Tag == "removable")
> {
> this.Controls.Remove(c);
> }
> }

You can't use a foreach and remove controls (or anything from a collection, for that matter). It changes the items in the list and you'll have problems like you're seeing. Use a for loop instead and loop from the last element to the first.