I found these lines help me debug all my hls streams:
Added to video screen object:
syslog = CreateObject("roSystemLog")
syslog.SetMessagePort(screen.GetMessagePort())
syslog.EnableType("http.error")
syslog.EnableType("http.connect")
while true
msg = wait(0, screen.GetMessagePort())
'DEBUG
if type(msg) = "roSystemLogEvent"
print type(msg)
print msg.GetInfo()
print msg.GetData()
print msg.GetMessage()
end if