~$ java -Xmx1024M -Xms512M -cp minecraft.jar net.minecraft.LauncherFrame
java.io.FileNotFoundException: /home/matthew/.minecraft/lastlogin (No such file or directory)
    at java.io.FileInputStream.open(Native Method)
    at java.io.FileInputStream.<init>(FileInputStream.java:137)
    at net.minecraft.LoginForm.readUsername(LoginForm.java:131)
    at net.minecraft.LoginForm.<init>(LoginForm.java:76)
    at net.minecraft.LauncherFrame.<init>(LauncherFrame.java:30)
    at net.minecraft.LauncherFrame.main(LauncherFrame.java:158)
Exception in thread "Thread-7" java.lang.NoClassDefFoundError: tr
    at net.minecraft.client.Minecraft.<init>(SourceFile:137)
    at m.<init>(SourceFile:33)
    at net.minecraft.client.MinecraftApplet.init(SourceFile:33)
    at net.minecraft.Launcher.replace(Launcher.java:143)
    at net.minecraft.Launcher$1.run(Launcher.java:87)
Caused by: java.lang.ClassNotFoundException: tr
    at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
    ... 5 more