I'm not sure, but the project pages says:
WebCDR for SwyxWare is a web based tool to display the content of the SwyxWare Call Detail Records (CDRs).
The current version makes use of an Apache Webserver and PHP. We are going to provide an ASP version for the Microsoft Webserver (IIS) as well.
source
So, probably, it needs a version of Apache...
But... For a project that is so Windows / Microsoft based, I agree one would expect it to run IIS/ASP...