This is most likely a result of the Default drive letter being F: in automation. If your system has a few drives in it then when we try to map F: to the network on the client there will be an error noting that the drive is already in use.
If you install HF1 and then rebuilds your automation environment the new default is supposed to be M: This may not be the only issue but I would recommend you to try this first.
Link to HF1 document is here. You can download it from the trial pages and install it to his trial no HF1 install.
http://www.symantec.com/docs/DOC8871
Link to a long discussion on the ways to manually change the drive letter here. (ds6.9 but same steps)
http://www.symantec.com/connect/forums/change-default-drive-mapping-automation-partition
What boot meathod are you using? PXE, USB automation disk, or Enbeded automation partition?
Also take a look at the following known issues list for more items to be aware of.
https://www-secure.symantec.com/connect/forums/gss-30-known-issues-please-read-first-posting
Thanks