Question : Windows Server 2008 Backup

I'm having an issue backing up over the network.  If I try to schedule a backup I cannot choose the shared network folder to backup to.  But if I click to Backup Once then I can specify that network folder and it works fine.  I need to schedule so that it will backup every night.  The network folder that I'm backing up to is a XP Pro machine.

Answer : Windows Server 2008 Backup

Backup to network is supported only for full backups. Pitily. Even in 2008 R2. It means if you backup to a network the latest version will overwrite the older one.
With other words if you need a backup job with full and incremental (or differential) backups strategy you are still bound to a local disk. And it means local dedicated disk.