drdetroit

Reinstall LCPDR, this time Run as Admin (right click the installer, select "Run as Admin".).
 
Also, make sure your GTAIV (or EFLC) root folder is not set to Read Only.  Uncheck that box and then install LCPDFR.
 
EDIT:  BTW: try replacing the modded car to the original and see if you still crash.  Id do that before reinstalling LCPDFR.  Some modded vehicles can just mess up your game.
 
DrDetroit
 

Right click the LCPDFR installer, go to properties, and make sure it's set to "run as admin".
 
Also, makes sure your root GTAIV/EFLC folder is not set to read only.  Go to properties and uncheck "read only", and let it do it's thing, then reinstall LCPDFR, running that as Admin.
 
Good Luck!
 
DrDetroit

Left-ALT+M for menu.  U to select primary patterns, I to select secondary patterns and O to select wig-wag patterns.  [ will turn on the primaries without any pattern (forget the name) and ] is your take-down lights (bright whites).  
 
Almost forget: J turns on the light patters (hit J 3times to get to primary patters) and H turns on sirens.  T will let you blurp your siren when needed.
 
It's good you have your scripts and ELS in order now.
 
DrDetroit

That's the exe...use LaunchGTAIV, not GTAIV.  Applications are generally, if not always, .exe.
 
DrDetroit

Run the G17 Diagnostics tool and post the results.  Also, post your scripthook text file and system specs..  Don't attach the text files, use a spoiler tag or just copy and past to your message.  Most peeps will not DL an attachment from somebody we don't know.
 
Also, is your GTAIV a legit copy or pirated?
 
Good day,
DrDetroit

I think that's an issue with the LCPDFR server.  The game sends data to LCPDFR server to keep track of your in-game stats.  It will not effect game play, but I don't think the stats are collected when you see that error, since the server is down when that error pops up in the username of the car's computer. 
 
Good day,
DrDetroit

MyDocuments/Rockstargames/GTAIV/Savegames
 
Good Day,
 
DrDetroit

Break out $19 and buy the damn game.  You people (thieves) are the reason companies like R* don't want to release their code for the PC.
 
DrDetroit

Yea, Game Booster does very little.  It actually makes my system lag when I run it.  I manually shutoff unneeded processes and applications,
 
Try using MemTurbo4, which is very effective.  Set the Auto Recover Level to 55m and Target Free Ram to 55m as well (as close to those numbers as you can get the sliders).  Then Apply and run the Deep RAM Scrub and after that Optimize button.  In the Config settings Deselect the option "Don't Auto Recover Unless CPU is Below XX".  It cured my setup of all texture loss/popping and increases FPS.
 
You'll notice that you'll get at least an extra 10%-15% RAM and will cure most of the issue that have to do with the memory leaks GTAIV has.
 
Good luck,
 
DrDetroit