When trying to run a standalone install of ASP.NET MVC 2 RTM on Windows 2003 Std x64 SP2 I ran into a problem where the install would fail but the installer reported nothing useful as an error.  [As soon as I can replicate this again I'll post a screenshot of the aforementioned useless error].

The install log was also fairly useless, except for the benefit of indicating where the installation source was unpacked.  For me this was C:\TEMP\2\VSD1.tmp\.  From the message in the first screen of the installer I was aware that it was going to install 2 items: the ASP.NET MVC2 runtime and the ASP.NET MVC 2 Visual Studio 2008 Tools and there were folders in \VSD1.tmp corresponding to each with an .msi in each of them.  So I figured I'd give it a go and run the .msi's individually to see if they provided a more detailed message of what was going on.

The first thing I ran was the runtime installer (\VSD1.tmp\MvcRuntime\AspNetMVC2.msi).  Right away it failed with the dreaded "Another installation is pending.  You must complete the previous installation before continuing" MSI message.  Bingo.  Pulled up task manager and sure enough, there was a hung msiexec process (um, from 3 months ago...).  After killing that (DIE SYMANTEC ANTIVIRUS, DIE!) the RTM package installer ran just fine and installed both components with no further issues.

Looking back, event log messages were also logged by MSI that gave a better indicator of what was happening:

Type: Error
Source: MsiInstaller
Category: None
Event: 11500

Product: Microsoft ASP.NET MVC 2 -- Error 1500. Another installation is in progress. You must complete that installation before continuing this one.