I tried installing it 2 times and it keeps on popping out failed to find a valid installation. Please use the browse option to locate your game installation. What should I do?

Hmm... what did you buy it on (steam or the CD etc.) You could try browsing the file location of GTA IV. If that doesn't work post back here and we'll see what we can do.

If it can't find your installed game, then you'll need to find it.. so use the browse option, go to where your game is installed Disc version is My Computer - Program Files x86 - Rockstar Games - Grand Theft Auto IV (or Episodes From Liberty City if you're using EFLC)

 

If you're using Steam version then it'll be - My Computer - Program Files x86 - Steam - Steam Apps - GTA IV (or GTA EFLC if you're using the EFLC game). after it is detected you'll be able to install it.

 

An alternative is to download the manual install version of LCPD:FR 1.0c and install it manually by using this guide - '?do=embed' frameborder='0' data-embedContent>>