Personally, I hate the 1603 error because it's a vague error message. It basically means, it won't install because of something.
In this case, we checked out the log file and found the dreaded 1603 error and found out what component failed during the installation:
2012/8/13:12:56:33 engineer2 DANB-HP Installing .NET Framework Runtime 4.0 KB2468871: D:\3rdParty\NET\4\wcu\dotNetFramework\NDP40-KB2468871-v2-x64.exe /q /norestart
2012/8/13:12:56:52 engineer2 DANB-H Install .NET Framework Runtime 4.0 KB2468871 Failed Installation aborted, Result=1603
In this case, the solution was relatively easy....
1. We tried to install the KB manually and there was still an error. The installer was located here:
2. Because the update didn't work, we then uninstalled the .NET 4.0. This would install a default (clean) .NET 4.0 and this version of .NET would allow the KB to update properly.
Thanks to Amy Satoff for confirming that this workflow helped.
Launch your Control Panel
-> Add/Remove Programs (XP) or Programs > Programs and Features (Windows 7)
2) Select and uninstall Microsoft .Net Framework 4 Extended
3) Select and uninstall Microsoft .Net Framework 4 Client Profile
4) Reboot your system after uninstalling both the components.
5) Install Autodesk software and this will successfully re-install .Net