I checked the 'Messages" and this is what I read:

9/25/2009 1:15:01 AM|rosetta@home|Message from server: (reached daily quota of 6 results)

The maximum daily quota for each cpu is 100 per day. The quota is reduced with each failure until it reaches one. This is to keep unattended machines from endlessly trashing hundreds of workunits. The quota is doubled with each successfully completed task so once you fix whatever is causing the problem your quota will quickly rise to 100 again.

As to the problem, take a look at your tasks list and notice it lists client error under the outcome column and downloading under the client state column for every task. Now go to the far left column(task id) and click on a task number for the details. The .exe file is most likely being blocked by either your firewall or antivirus program. Solve that and soon you'll be crunching for rosetta all day.

Snags