If you try to access a DFS resource using cifs you may bet this error:
mount error(11): Resource temporarily unavailable
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)
I used to think that DFS access was still not mature enough until today, when I googled for this error and found that if I installed keyutils this error would disapear and everything would work ok. I thought this would not apply to me but it looks that it did.
So, this may apply to you as well if you are running a recent enough Debian and/or kernel, I'm currently running Squeeze with it's 2.6.32 kernel.
If it doesn't: check for CONFIG_KEYS=y and CONFIG_CIFS_DFS_UPCALL=y on your kernel config and for recent cifs-utils and keyutils packages (squeeze version works ok)
Hope this helps.