Macbook pro boot with kernel panic - can't perform kext scan

I was trying to swap command and option key for my external keyboard following the instruction in http://hints.macworld.com/article.php?story=20110529094802391.

When I'm done with change and I restarted, my mac booted with Kernel panic message. I'm sure I've messed the info.plist file. Now I cannot boot in safe mode as well.

I know if I get a way to change the file it should be fine.

The message shown in screen is

panic(cpu 0 caller 0xffffff80002c4794): Kernel trap at 0xffffff80005eae1e, type 14=page fault, registers: ...

Debugger called: <panic>

Backtrace (CPU 0), Frame : Return Addressd

...

...

can't perform kext scan: no kext summary

BSD process name corresponding to current thread: Unknown

Mac OS version:

Not yet set

Kernel version:

Darwin Kernel Version 11.4.2: Thu Aug 23 16:25:48PM

Kernel UUID: ...

System uptime in nanoseconds: 11...

Thanks