Samba mount dropping

[IndieSchmindie]

Hi,

On Ubuntu 11.10 server I have a mount in my fstab to a share on an XP PC.

//192.168.0.22/iTunes /media/iTunes smbfs username=xxx,password=xxxx 0	0

It's fine every boot and generally speaking for about a day on average at which point it drops and I have to do a sudo mount -a

What is the best way of debugging this? Nothing I can really find in /var/log/syslog

Thanks