Unhappy [Help] Phone wont boot (error mounting sdcard)

Hello,

today my phone didn't boot after i restarted it, i kept trying for around 1h on my way home.. and nothing. After meddling around in the recovery mode i noticed the sdcard wasn't mounting. Already tried to use Adb to mount it and get the error aswell.

Rom: cyanogenmod 10.1 or 10.2
Phone: nexus S

errors:

Failed to open /sys/cass/android_usb/android0/state: no such file or directory
Error mounting /sdcard|