What is the 'java.lang.UnsatisfiedLinkError' and how can I fix it in Minecraft?

An 'java.lang.UnsatisfiedLinkError' typically arises when the Java Virtual Machine (JVM) tries to load a native library (written in a language like C++) that it cannot find or load. This is often seen with certain mods that rely on external libraries. Ensure all required libraries for your mods are installed correctly, and check for mod compatibility with your Java version and Minecraft version.