Before following instructions below, try to follow these steps:
1. Be sure to have the newest .NET Framework, DirectX and Microsoft Visual C++ Redistributable Packages updates installed.
2. Try to delete smaa.dll
3. Try to delete dsound.dll & install xliveless instead: http://goo.gl/2d93iD
4. Try to re-install your current patch (links below)
5. Try to re-extract the files from CryENB V2's _Install folder to your main GTA IV/EFLC folder.


INSTRUCTIONS:
First delete EVERYTHING from your GTA IV/EFLC main folder.

Then re-install the game and download patch 1.0.7.0 if you use the original GTA IV or patch 1.1.2.0 if you use EFLC:

GTA IV 1.0.7.0 link:
http://updates.rockstargames.com/patches/eflc/update2_EN.zip
EFLC 1.1.2.0 link: http://updates.rockstargames.com/patches/gtaiv/title_update_7_EN.zip

Then extract the patch files to your GTA IV/EFLC main folder and install the patch. When done, start the game BEFORE installing any mods at all and then close the game again.

If you were able to launch the game properly then install CryENB V2 and see if it works (it should, it works for me every time). If it works you can start installing other mods too :) Good luck!


If that didn't work, contact me:
Facebook: https://www.facebook.com/fabriciuzgraphics
Website: http://fabriciuz.wix.com/fabriciuz
Email: damgaard.marc@gmail.com
And i will try to help you out personally.