missing message port problems

i've run into a strange problem where my program is making no responses when running a particular screen, specifically a grid with several video listings. I've tried a few things to root out the problem but nothing seems to stick. Here is the code I have

sub CreateRecentMenu()
	screen = CreateObject("roGridScreen")
	port = CreateObject("roMessagePort")
	xml = CreateObject("roXMLElement")
	xml_str = CreateObject("roString")

	link_str = "[url removed for privacy purposes]"

	xml_str = GetXML_1(link_str)
	json = ParseJson(xml_str)
	recent = GetRecentSermons(json)

	screen.SetGridStyle("flat-landscape")
	screen.SetupLists(1) 'more lists will be added in the near future, but i am only using one row for now
	screen.SetListNames("Recent Teachings")
	screen.SetContentList(0, recent)

	screen.show()

	while(true)
		msg = wait(0, port)
		if(type(msg) = "roGridScreenEvent")
			if msg.isListItemFocused()
				print "focused " + recent[msg.GetData()].Title
			else if msg.isListItemSelected()
				print "selected " + recent[msg.GetData()].Title
			else if msg.isScreenClosed()
				print "closed Recent menu successfully"
				return
			end if
		end if
	end while

	return
End sub

Again, i'm absolutely not sure what could be causing this issue i'm having. I've attempted to print out type(msg) several times to learn what type of event the screen is getting but it gives me nothing in response. Any thoughts would be appreciated.