Will ResCartaWeb interfere with my IIS installation?

 No, ResCartaWeb runs under the Apache Tomcat server, so there is required interaction with IIS.

 You can, however, use tomcat as a service which is called from IIS.  This will allow you to forgo the dreaded default 8080 address. Using IIS as a front end to your tomcat will also allow the use of Windows^R authentication if needed.