There is a complete & simpler way to do this using PowerShell.
This code will export ALL report content in the exact same structure as the Report server. Take a look at the Github wiki for other options & commands
#------------------------------------------------------
#Prerequisites
#Install-Module -Name ReportingServicesTools
#------------------------------------------------------
#Lets get security on all folders in a single instance
#------------------------------------------------------
#Declare SSRS URI
$sourceRsUri = 'http://ReportServerURL/ReportServer/ReportService2010.asmx?wsdl'
#Declare Proxy so we dont need to connect with every command
$proxy = New-RsWebServiceProxy -ReportServerUri $sourceRsUri
#Output ALL Catalog items to file system
Out-RsFolderContent -Proxy $proxy -RsFolder / -Destination 'C:\SSRS_Out' -Recurse