How to install Inmagic Webpublisher 12 on Windows 7
Disclaimer: Not officially supported. Plunging heedlessly on...
1 - Back up INI files
First back up all your .ini files. Be sure you are getting the CORRECT copy of the ini file: the ini files in the Program Files directory are access-protected in Vista and Win7 because the Program Files area is a forbidden zone. You must open the ini file with elevated privileges, like with Notepad "run as administrator", and save it somewhere safe.
- dbtwpub.ini
- inmagic.ini
- dbtext.ini
2 - Upgrade from previous version
If you want to upgrade from previous version of WPP instead installing a fresh copy, uninstall the previous version MANUALLY first, because the WPP 12 installer tries to uninstall without elevated permission, and thus fails.
3 - Run installer as admin
Run the WPP 12 installer with administrator privileges. If you have a setup.exe you can right-click to "run as administrator".
My preview version of the installer is an *.msi file only, which doesn't have a right-click "run as admin" option. Instead, I launch the msi with msiexec from an elevated command prompt:
- Search for "cmd.exe" from Windows Start Menu
- Right-click cmd.exe and "run as administrator"
- Change directory to location of the msi, e.g. cd c:\users\ptyrrell\downloads
- Run the msi with the msiexec /i option, e.g. msiexec /i "Inmagic DBText WebPublisher PRO.msi"
4 - Fulfill prerequisites
The installer is cleverer than previous versions when checking for prerequisites, so you'll probably have to go and install or enable various Windows features before continuing. 
IIS 6 Compatibility (IIS7 only) seems to be satisfied by enabling the "IIS Metabase and IIS 6 configuration compatibility" Windows feature.
Be warned: if you don't run the installer with elevated privileges, you will continue to fail the prerequisite check even after installing/enabling the right prerequisites!
5 - Test the install
Restore your backed up ini files. Run a query on the sample cars textbase to ensure WPP is returning results as expected.
If you are installing on a 64 bit machine, you need to enable 32 bit applications on the relevant application pool as covered in this previous post called How to Install Webpublisher on 64-bit IIS 7.
6 - Be the star you know you are
You did it! Now cut out a cardboard star with safety scissors, pencil "STAR HACKER" on it, and get your mum to pin it to your chest, glitter optional. Salute yourself in the mirror. Star! Hacker!