Sounds like an issues of the switch, as The Dude does not send any non-standard packets. Any SNMP query/query used to monitor other services could make your switch crazy and reboot it.
I would recommend to upgrade the firmware on the switch, then work with the switch manufacturer on the problem.
3COM is dead and taken over by HP. I still have over 40 3COM switches and most are 4400 or 4900. The dude worked fine until an update. You can blame it on the switches which is always the easy path. Or you can take credit for the issue and see it through. This product rebooted over 30 of my switches midday after a scan. I shut down this product and everything fine since. So if it's not your product then why does it stop when it's not running. Faulty switches right! All 30 something of them. All the firmware is upgraded.