This post’s information is a bit old but I dug this out of an old email (12/15/2008) I had and figure it’s worth posting:
I found a bug in Office Communicator Web Access Manager (2007 release) today.
Within the deployment wizard (via CD) and this management tool, you have the option of creating virtual directories for Internal or External access. The automated creation for internal sites work fine but external does not.
When you create an internal site, the ASP.NET tab in IIS selects the appropriate version as shown below.
However, when you’re creating external sites, the wizard does not automatically select the ASP.NET version:
What happens is when you try to access the site, you will get a Page cannot be displayed. I have found no KB article for this on Microsoft’s site.