Hey man, i am having the exact same problem as you i believe.
I posted a topic that no-one seems to respond to, so i think i shall just mention it in here too. From My Topic
Okay, so recently i had to re-install my GTA IV for unknown reasons, and when i reinstalled my GTA IV, i updated to the latest patch [18.104.22.168]
Now, everything has installed properly so i presume, but now, because the new update allows you to not need to use the RGSC application to launch the game, every time i double click on 'LaunchGTAIV.exe' nothing happens. The game won't load or anything, it acts as though i haven't clicked anything.
Here is what my Grand Theft Auto IV folder looks like.
If there is any solution to this problem that someone knows, could you please inform me, sorry if this is in the wrong section.
It has been the second time i have re-installed this since this error. Therefore i have had this problem two times.
So as you can see, it seems that me and ItalianStalion have the same problem here, or very similar.
I am getting EFLC for PC soon anyway, but i would like to know why GTA IV does not start up....at all!
When i tried running gta4.exe, it came up with that RMN60 error that ItalianStalion gets. Then when i try running LaunchGTAIV.exe after that, i get another message saying that "GTA4.exe has encountered a problem and needs to close. We are sorry for the inconvenience."