There are several problems in your code:
1. 1ms interval is too short for a timer. It may cause the main thread to be blocked by this timer.
2. Your code actually creates many timers with this interval:
Case "WP" 'work in progress
myTimer.Initialize("tim",1)
myTimer.Enabled = True
You are creating a new timer with this interval each tick. You don't need to initialize a new timer for the timer to continue ticking.
3. It is not really a problem however the timer is not needed here at all. Use the DownloadCompleted event to update whatever you want to update.