Error in Internet Information Services (IIS) using Web Farm Framework : "Exception in response stream.The ApplicationHost.config file is invalid"

$bV3Installed = $false
$bV2Installed = $false
$strSvcVersion = ""

$RegLoc = Get-ChildItem HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall
$Programs = $RegLoc | foreach {Get-ItemProperty $_.PsPath} 

Foreach ($name in $Programs)
{
if($name.DisplayName -eq "Microsoft Web Deploy 3.0")
{
$bV3Installed = $true
}

if($name.DisplayName -eq "Microsoft Web Deploy 2.0")
{
$bV2Installed = $true
}
}

$RegLoc = Get-ItemProperty HKLM:\System\CurrentControlSet\Services\MSDEPSVC
$strSvcVersion = $RegLoc.Description

if($bV3Installed -eq $true -and $bV2Installed -eq $true)
{
"Please uninstall Microsoft Web Deploy 2.0 and Microsoft Web Deploy 3.0 and reinstall Microsoft Web Deploy 2.0 from here: http://www.microsoft.com/en-us/download/details.aspx?id=25230"
}
elseif($bV3Installed -eq $true -and $bV2Installed -eq $false)
{
"Please uninstall Microsoft Web Deploy 3.0 and install Microsoft Web Deploy 2.0 from here: http://www.microsoft.com/en-us/download/details.aspx?id=25230"
}
elseif($bV3Installed -eq $false -and $bV2Installed -eq $true -and $strSvcVersion -eq "Remote agent service for the Microsoft Web Deploy 3.0.")
{
"Please uninstall Microsoft Web Deploy 2.0 and reinstall Microsoft Web Deploy 2.0 from here: http://www.microsoft.com/en-us/download/details.aspx?id=25230"
}
elseif($bV3Installed -eq $false -and $bV2Installed -eq $true -and $strSvcVersion -eq "Remote agent service for the Microsoft Web Deploy 2.0.")
{
"Microsoft Web Deploy 2.0 is installed correctly"
}
else
{
"Microsoft Web Deploy is not installed, it can be installed from here: http://www.microsoft.com/en-us/download/details.aspx?id=25230"
}