I have followed all of the points, that you gave me! But it is still the same problem. When I start Gta 4 and push ingame ALT+P nothings happened. Its like the Mod isn't installed. I have tested both istaller, manual and automatic.
My System: Notebook/ Acer Aspire/ Windows 8 64-Bit/ processor: Intel Core i5 -3210M CPU @ 2.50GHz 2.50GHz/ random access memory: 8GB/ NVIDIA geforce gtx 660m
At this time I dont use any other Mods!