Acts like One Unit

Hello,

I have 4 GTX480s folding with tracker. Recently Tracker started running a single unit on each GPU and SMP, then stop. OneUnit is disabled, and I verified in the config file.
For example, I come back to Tracker in the morning, and all tasks are stopped. Each has a log entry similar to below:
[07:06:10] + Processing work unit
[07:06:10] Core required: FahCore_15.exe
[07:06:10] Core found.
[07:06:10] Working on queue slot 01 [March 10 07:06:10 UTC]
[07:06:10] + Working ...
[07:06:10] - Calling '.\FahCore_15.exe -dir work/ -suffix 01 -nice 19 -priority 96 -nocpulock -checkpoint 3 -verbose -lifeline 5240 -version 630'
[07:06:10]
[07:06:10] *------------------------------*
[07:06:10] Folding@Home GPU Core
[07:06:10] Version 2.20 (Tue Aug 2 12:06:37 PDT 2011)
[07:06:10] Build host SimbiosNvdWin7
[07:06:10] Board Type NVIDIA/CUDA
[07:06:10] Core 15
[07:07:21] Starting GUI Server
[07:07:33] CoreStatus = 63 (99)
[07:07:33] + Error starting Folding@home core.
[07:07:33] Folding@Home will go to sleep for 1 day as there have been 5 consecutive Cores executed which failed to complete a work unit.

Mine has been doing the same thing recently as well. I have to stop the client and restart or sometimes I have to delete the WU and start over. Usually deleting the WU and letting it start over works, but it's killing my PPD...

I am about to download and reinstall.