I think Forge may have an issue with a UNC path for the .minecraft folder. I run my minecraft instances from a NAS because there are 3 players on 4 different computers in the house and they move around. I use the batch file trick of setting the appdata path to the path to get it all to run from the directory. After an installation of Forge, I get an app crash upon running the Forge profile. If I do a drive mapping to the NAS path instead of using the UNC, it works.
I did not find any other articles with the same beginning error line that were close to relevant in time or version. I did find this on Stackoverflow of a person that had that Java type error and it was because they had a UNC path, which is what prompted me to try the drive mapping. http://stackoverflow.com/questions/2366270/what-does-uri-has-an-authority-component-mean
Steps to produce:
Get a network location set up (ex \\nas\minecraft\testfolder)
Create a batch file with the below example named runme.bat in the testfolder
Download the latest Minecraft.exe and put into the testfolder path
Run the runme.bat file
Launch the default profile once to get everything initialized
Quit Mincraft and Launcher
Run the Forge installer and install into the \\nas\minecraft\testfolder\.minecraft path
Run the runme.bat file
Choose the new Forge profile and launch it
Environment:
Windows 8 Pro
Java 1.7.0_25
Minecraft.exe downloaded on 8/25/2013. 661k in size
Launcher 1.2.1
Forge Installer: minecraftforge-installer-1.6.2-9.10.0.804.jar
Runme.bat contents
Minecraft crash report
ForgeModLoader-client-0.log contents
