Get-ADReplicationSubnet problem with custom object

Hi,

I'm writing a script which builds a AD Domain Structure.

In order to build a Site/Subnet structure, I import a list of Subnets from a csv file and, before creating the subnet, I checked if it does not already exist. The problem is that the cmdlet does not interpret information retrieved from the csv file.

$SitesToCreate = import-csv $filePath -Delimiter ";"
Foreach($Site in $SitesToCreate){
    if (!$(Get-ADReplicationSubnet -Filter {Name -eq $Site.Subnet})) {
       New-ADReplicationSubnet -Name $Site.Subnet -Site $Site.Name -Location $($Site.Country+ "\" +$Site.Name)
    }
}

The error returned by the script engine is the following :

Get-ADReplicationSubnet : Property: 'Subnet' not found in object of type: 'System.Management.Automation.PSCustomObject'.

obviously the property "subnet" exists.

Do you have any idea about the error ?

By advance, Thank you