By looking at the code you pasted and the fact that your calling a bunch of feeds, my guess is that the PublishDate property might be null or returning a date format that can't be parsed.
Try checking for a null value on the DateFormat property.
By looking at the code you pasted and the fact that your calling a bunch of feeds, my guess is that the PublishDate property might be null or returning a date format that can't be parsed.
Try checking for a null value on the DateFormat property.