Alerts not firing
When I set up an alert, it never seems to fire - although the 'Test' button sends me an e-mail just fine.
Once you've set up an alert, you have to attach the alert to the IP address you want to monitor. This gives you the capability to use different alerts for different IP addresses.
To attach an alert to an IP, trace to the host you're interested in. Then right-click on the hop you want to monitor. Select 'Watch this host (Alerts)...'.
Then select an alert (or multiple alerts) from the list. This should put a [...] around the hop that's being monitored.
If you always want an alert to watch any target you trace, then you can do this by going to your alert setup (Edit -> Alert Setup...), find the alert you want to have watch all targets, and then hit the 'Show Targets' button. In there, add 'ALL' to the list of targets you want monitored.
For a detailed explanation of alerts go here.