I installed Kiln on top of an existing FogBugz installation (which was already version 8.3.42). The installer initially failed, but that had to do with the database user. I restarted the installer, fixed the setting and tried again; this time it completed the installation, after which I got the screen telling me to install the licenses.
My browser opened at http://[myserver]/Kiln/Setup/Go, but that page was really messed up, no CSS has been loaded and I get script errors.

After I enter my user name and password and click 'Log On', I get this:

Looking in IE's Developer Tools on the setup page, I can see all of the CSS and JavaScript links result in 404 pages.
For reference (since it seems to contain useful information), here's the source of one such page (staticJS.asp?sFiles=6,7,8,0,1,2,3,4,5,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25&lang=en-US&20110201180417):
<html>
<head>
<title>The resource cannot be found.</title>
<style>
body {font-family:"Verdana";font-weight:normal;font-size: .7em;color:black;}
p {font-family:"Verdana";font-weight:normal;color:black;margin-top: -5px}
b {font-family:"Verdana";font-weight:bold;color:black;margin-top: -5px}
H1 { font-family:"Verdana";font-weight:normal;font-size:18pt;color:red }
H2 { font-family:"Verdana";font-weight:normal;font-size:14pt;color:maroon }
pre {font-family:"Lucida Console";font-size: .9em}
.marker {font-weight: bold; color: black;text-decoration: none;}
.version {color: gray;}
.error {margin-bottom: 10px;}
.expandable { text-decoration:underline; font-weight:bold; color:navy; cursor:hand; }
</style>
</head>
<body bgcolor="white">
<span><H1>Server Error in '/kiln' Application.<hr width=100% size=1 color=silver></H1>
<h2> <i>The resource cannot be found.</i> </h2></span>
<font face="Arial, Helvetica, Geneva, SunSans-Regular, sans-serif ">
<b> Description: </b>HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable. Please review the following URL and make sure that it is spelled correctly.
<br><br>
<b> Requested URL: </b>/kiln/Setup/staticJS.asp<br><br>
<hr width=100% size=1 color=silver>
<b>Version Information:</b> Microsoft .NET Framework Version:2.0.50727.4952; ASP.NET Version:2.0.50727.4955
</font>
</body>
At the bottom, the following is enclosed in a comment (I can't literally paste it here):
[HttpException]: A public action method 'staticJS.asp' could not be found on controller 'Kiln.Controllers.SetupController'.
at System.Web.Mvc.Controller.HandleUnknownAction(String actionName)
at System.Web.Mvc.Controller.ExecuteCore()
at System.Web.Mvc.MvcHandler.ProcessRequest(HttpContextBase httpContext)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
If I simply go to FogBugz and log on there, nothing related to Kiln shows up, and I can't enter the license information, I get the following error:
We were unable to find an order with the email and order info you sent. Click here to look up your order number if you do not know it.
What have I done wrong? Our server has a new Windows Server 2008 R2 x64, along with SQL Server 2008 (not R2).