Weathercat asking for restart after reporting "hardware problems"

[cabut]

I got this message that Weathercat is encountering hardware problems and suggests a restart after running a few hours. I have to force quit WC and try to restart at which time my iMac hangs and I get the blue screen of death. I have to hold down the start button and shut it down. This happened two days in a row. I have a Monitor 2 that seems to be working fine. I am running Snow Leopard. Any ideas what this could be?
I am attaching a partial log from the console

Tom

[WCDev]

Looks like the serial to USB converter driver has crashed Tom. USB drivers live in kernel space so when they crash, the machine is unstable and needs to be rebooted.

First check the hardware itself (clean contacts, all properly secure, possibly try another USB port) then check for an updated driver from the manufacturer of your dongle.

[cabut]

Like many, I am using the Keyspan Two Port Din8: USA-28XG adapter with the latest driver for Snow Leopard 10.6.8. All my hardware connections seem to be secure. I was running the same Monitor 2 hardware and serial connector on an iBook 10.5.8
with LWC2 with no problems until the iBook gave up the ghost with a burned out fan motor. So, I decided to switch to Weathercat. The only other possible problem I could think of is that my area has had uncharacteristically overcast skies for almost 4 days straight. Perhaps the 15yr. old solar powered Monitor 2 is not getting sufficient sunlight to power the external sensors or charge the battery?-Although when I scan through the readings on the Davis console, all look fine.