PowerShell XML Script always returns 0

Hello,

I have built a PowerShell script to monitor my SAN IOPS, but for some reason I cannot get PRTG to show the result value. The script basically runs a command to dump the IOPS of the SAN to CSV, and I then extract the information I need and write it out to XML.

Here is the script:

$outputFile = "C:\PRTG\MDoutput.csv"

Set-Location "C:\PRTG"
.\SMcli.exe hostname -S -quick -c "show allVirtualDisks performanceStats;" > $outputFile

#remove first line in file
$csv = Get-Content $outputFile
$csv = $csv[1..($csv.count - 1)]
$csv > $outputFile

#remove all blank lines
Select-String -Pattern "\w" $outputFile | ForEach-Object {$_.line} | Set-Content "C:\PRTG\MDoutput2.csv"
del $outputFile
rename-item "C:\PRTG\MDoutput2.csv" $outputFile

$string1 = Import-CSV $outputFile | ? {$_."Storage Arrays " -eq "STORAGE ARRAY TOTALS"} | ForEach-Object {
foreach ($property in $_.PSObject.Properties)
{
    if ($property.Name -match "Current IO/second")
    {
        $iops = $property.Value
    }
}
}

Write-Host "<prtg>"
 
Write-Host "<result>"
Write-Host "<channel>Current Storage IOPS</channel>"
Write-Host "<value>$iops</value>"
Write-Host "</result>"
 
Write-Host "</prtg>"

I can run the script from the PRTG Server manually with no problems, and it shows the following output (which I was expecting):

<prtg>
<result>
<channel>Current Storage IOPS</channel>
<value>164.0</value>
</result>
</prtg>

I have also enabled the "Write EXE result to disk" to make sure that the script is running OK within PRTG; again it shows the following information within the log file:

<prtg>
<result>
<channel>Current Storage IOPS</channel>
<value>164.0</value>
</result>
</prtg>

No matter what I do I can't get PRTG to show the correct value, and it always shows 0. See screenshot: https://dl.dropboxusercontent.com/u/3265030/Capture.PNG.

Any help on this would be greatly appreciated.