Windows .jar Crash when creating new world - only when entering a seed

[mouseodoom]

Hey yall, windows 7 64 bit here, when I use the launcher to start MC and create a new single player world, the app crashes.

FTB Launcher version (if this isn't the newest update update and try again): 1.0.7 (happened in previous version as well)​

Minecraft Version: 1.4.2​

Java version: 1.6.0_29​

Detailed description of the issue / how can the issue be recreated:​

1.. Create a new single player world.​

2. I enter a seed with alphabetic characters (I use the US/Eng character set), not numbers.​

-Many, many examples: Yarp, rawr, Milarepa, Alexandria, I've got a monkey, ooh! - the name does not seem to matter​

​

3. After the crash, the world exists and is totally playable. i just have to close MC, relaunch FTB and select that world​

-this does not happen if I enter a seed using numbers instead of characters​

Here's the crash log:

http://pastebin.com/YQkL9QRC

 

[Backplague]

Are you sure your keyboard doesn't have any keys stuck pushed? The log tells that the world name/seed contains invalid letters.

 

[damnedsky]

This is indeed a very weird bug. Did you copy a MultiMC instance in the Launcher folder by any chance?

 

[mouseodoom]

I erased my launcher folder and cleared out %/AppData/Roaming/ftblauncher while troubleshooting something else last night. No multiMC and no keys are stuck on my keyboard (I typed this on the computer I run FTB). Everything in the FTB launcher folder should be default