Help Needed in compilation when TARGET_BUILD_VARIANT is set as "user".

defining DISABLE_DEXPREOPT=true in your environment, this will disable the Dex pre-optimization pass that needs to run in the emulator
have downloaded the code from http://source.android.com/ and
try to compile the TARGET_BUILD_VARIANT as user.

I got the following error. It seems emulator is not working. I am
newbie to Android. Please suggest me some pointer to resolve this.

praveen <at> ggns1gpr01:~/mydroid$ make PRODUCT-littleton-user
build/core/product_config.mk:211: WARNING: adding test OTA key
============================================
TARGET_PRODUCT=littleton
TARGET_BUILD_VARIANT=user
TARGET_SIMULATOR=
TARGET_BUILD_TYPE=release
TARGET_ARCH=arm
HOST_ARCH=x86
HOST_OS=linux
HOST_BUILD_TYPE=release
BUILD_ID=
============================================
build/core/main.mk:180: implicitly installing apns-conf_sdk.xml
Install: out/target/product/littleton/system/app/IM.apk
Dexpreopt ramdisk: out/target/product/littleton/obj/PACKAGING/
dexpreopt_intermediates/ramdisk.img
out/host/linux-x86/bin/mkbootfs out/target/product/littleton/obj/
PACKAGING/dexpreopt_intermediates/root | gzip > out/target/product/
littleton/obj/PACKAGING/dexpreopt_intermediates/ramdisk.img
dexpreopt: copy system to out/target/product/littleton/obj/PACKAGING/
dexpreopt_intermediates/system
dexpreopt: optimize dex files
02:09.827260 dexpreopt: Creating data image
1+0 records in
1+0 records out
33554432 bytes (34 MB) copied, 2.09668 seconds, 16.0 MB/s
02:12.195519 dexpreopt: Running emulator: /home/praveen/mydroid/out/
host/linux-x86/bin/emulator -kernel prebuilt/android-arm/kernel/kernel-
qemu -ramdisk out/target/product/littleton/obj/PACKAGING/
dexpreopt_intermediates/ramdisk.img -image out/target/product/
littleton/obj/PACKAGING/systemimage_unopt_intermediates/system.img -
initdata out/target/product/littleton/obj/PACKAGING/
dexpreopt_intermediates/emutmp/data.img -data out/target/product/
littleton/obj/PACKAGING/dexpreopt_intermediates/emutmp/data.img -
system out/target/product/littleton -no-window -netfast -noaudio -
shell-serial fdpair:3:6
02:12.254468 dexpreopt: WaitForString: "#", 20.0
03:12.303239 dexpreopt: Timeout expired after 20.0 seconds
Emulator did not respond
03:12.360998 dexpreopt: Killing emulator
make: *** [out/target/product/littleton/obj/PACKAGING/
dexpreopt_intermediates/system.img] Error 1