I'm a very newbie in android ROMs, i'm trying compiling android source (aosp) on my ubuntu 10.04 64bit, everything is ok but after 2 hours from i do "make -j4 otapackage", i get an error,

out/host/linux-x86/bin/mkuserimg.sh: line 52: 26037 Floating point exception$MAKE_EXT4FS_CMD
make: *** [out/target/product/a760s/userdata.img] Error 4
make: *** Waiting for unfinished jobs....

And this is the content of the file mkuserimg.sh
$MAKE_EXT4FS_CMD // error at this line
if [ $? -ne 0 ]; then
exit 4

I have no idea about this error, please tell me how can i fix that, thanks so much.