You may already know this, but you have to unzip the patch before you can actually run it.
The file you download is called
in_memoriam_v2.3_pc_us.zipOnce you unzip
in_memoriam_v2.3_pc_us.zip you get a file called
in_memoriam_v2.3_pc_us.exeIt's the
in_memoriam_v2.3_pc_us.exe file that you have to run to install the patch.
(The ".exe" part may not display in Windows if you have extensions hidden.)
Once the patch is unzipped,
try copying the unzipped patch to the game folder before running it.
You may have to right-click it and choose "Run as Administrator" to get it to install. I don't have the game anymore, so I can't test how to install the patch on XP or Windows 7.
Assuming you installed the patch properly, it may be that there are other issues.
The patch has to be compatible with your version of the game. If you have the US version, which was called "Missing Since January" instead of "In Memoriam," the patch may not work correctly.
Patches-Scrolls says the patch is from 2013, but that may be the date it was uploaded and not the date it was created.
There are tips on getting it working one of the comments at the end of this review
http://justgamesretro.com/win/missingIt runs on windows 7 64 bit
1) make sure you configure all installers and resulting .exe files to run in XP Service pack 2 compatibility mode, and as Administrator.
2) You will have to update both shockwave, and quicktime to the latest versions after the game is installed.
3) you need to install the 2005 patch (which updates the game to use the correct servers) which is available from the game’s website
http://www.inmemoriam-thegame.com/gb/bre.htm