The Anaplan XL Reporting Web Edition installation program is a standard Windows Installer (MSI) program wrapped in a bootstrapper EXE. You can log any errors by using command line switches.
Windows installer (MSI)
"Anaplan XL Reporting Web Edition.msi" /l*v C:\LogFiles\Log.txt
Windows executable (EXE)
Anaplan XL ReportingWebEdition.exe /ComponentArgs "Anaplan XL Reporting Web Edition":"/l*v C:\log.txt"