Yes, it's the name of the host you want to boot using Auto Deploy. Yes, the software packages (VIBs) you see getting uploaded to the Auto Deploy server when you run the "new-depoyrule" cmdlet is the same as the ISO. Here's what I would suggest you do:
Deactivate your existing rule:
PowerCLI C:\> Remove-DeployRule Test
Import the software depot (with the default image profiles):
PowerCLI C:\> Add-EsxSoftwareDepot https://hostupdate.vmware.com/software/VUM/PRODUCTION/main/vmw-depot-index.xml
Create a new deploy rule that will apply to all hosts:
PowerCLI C:\> New-DeployRule –Name “Default-Image” –Item “ESXi-5.0.0-799733-standard” –AllHosts
Add the new rule to the active ruleset:
PowerCLI C:\> Add-DeployRule Default-Image
Update the Auto Deploy cache for any existing hosts:
PowerCLI C:\> foreach ($esx in Get-VMHost) {$esx | test-deployrulesetcompliance | Repair-DeployRuleSetCompliance}
Then try to reboot the host.