Okay, I'm having a major problem here. I want to install Optifine for Tekkit 1.5.2 (latest). The problem is when I put the files in the modpack.jar and then launch Tekkit. I get the usual screen saying "FML is setting up your minecraft environment", then a black screen, then a crash. When I try and install Optifine on other mod packs, the same thing happens. Here's the crash log: Minecraft has crashed! ---------------------- Minecraft has stopped running because it encountered a problem; Failed to start game A full error report has been saved to /Users/SaiNatarajan/Library/Application Support/technic/tekkitmain/crash-reports/crash-2013-08-14_12.11.14-client.txt - Please include a copy of that file (Not this screen!) if you report this crash to anyone; without it, they will not be able to help fix the crash --- BEGIN ERROR REPORT 1ea5adc1 -------- Full report at: /Users/SaiNatarajan/Library/Application Support/technic/tekkitmain/crash-reports/crash-2013-08-14_12.11.14-client.txt Please show that file to Mojang, NOT just this screen! Generated 8/14/13 12:11 PM -- System Details -- Details: Minecraft Version: 1.5.2 Operating System: Mac OS X (x86_64) version 10.7.3 Java Version: 1.6.0_51, Apple Inc. Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc. Memory: 45493216 bytes (43 MB) / 158638080 bytes (151 MB) up to 1065025536 bytes (1015 MB) JVM Flags: 2 total; -Xmx1024m -XX:MaxPermSize=128m AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used Suspicious classes: FML and Forge are installed IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0 FML: LWJGL: 2.4.2 OpenGL: Intel HD Graphics 3000 OpenGL Engine GL version 2.1 APPLE-7.18.11, Intel Inc. Is Modded: Definitely; Client brand changed to 'fml,forge' Type: Client (map_client.txt) Texture Pack: Default Profiler Position: N/A (disabled) Vec3 Pool Size: ~~ERROR~~ NullPointerException: null org.lwjgl.opengl.OpenGLException: Invalid value (1281) at org.lwjgl.opengl.Util.checkGLError(Util.java:56) at org.lwjgl.opengl.Display.swapBuffers(Display.java:645) at net.minecraft.client.Minecraft.func_71357_I(Minecraft.java:518) at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:407) at net.minecraft.client.MinecraftAppletImpl.func_71384_a(SourceFile:56) at net.minecraft.client.Minecraft.run(Minecraft.java:733) at java.lang.Thread.run(Thread.java:680) --- END ERROR REPORT a9823cad ---------- Thanks for the help.