heroku build error when installing libicu

hammady@hossams-air~/Workspace/herokutest$ heroku build . -b ddollar/multi -r
Checking for app files to sync... done, 0 files needed
Launching build process... done
Preparing app for compilation... done
Fetching buildpack... done
Detecting buildpack... done, Multipack
Fetching cache... empty
Compiling app...
=====> Downloading Buildpack: https://github.com/benjie/heroku-buildpack-apt
=====> Detected Framework: Apt
  Updating apt caches
    Get:1 http://archive.ubuntu.com lucid Release.gpg [189B]
    Get:2 http://archive.ubuntu.com lucid-security Release.gpg [198B]
    Get:3 http://archive.ubuntu.com lucid-updates Release.gpg [198B]
    Get:4 http://archive.ubuntu.com lucid Release [57.2kB]
    Get:5 http://archive.ubuntu.com lucid-security Release [57.3kB]
    Get:6 http://archive.ubuntu.com lucid-updates Release [58.3kB]
    Get:7 http://archive.ubuntu.com lucid/main Packages [1383kB]
    Get:8 http://apt.postgresql.org lucid-pgdg Release.gpg [836B]
    Get:9 http://apt.postgresql.org lucid-pgdg Release [25.6kB]
    Get:10 http://archive.ubuntu.com lucid/universe Packages [5430kB]
    Ign http://apt.postgresql.org lucid-pgdg Release
    Get:11 http://archive.ubuntu.com lucid-security/main Packages [549kB]
    Get:12 http://archive.ubuntu.com lucid-updates/main Packages [739kB]
    Get:13 http://apt.postgresql.org lucid-pgdg/main Packages [30.9kB]
    Fetched 8332kB in 2s (3245kB/s)
    Reading package lists...
W: GPG error: http://apt.postgresql.org lucid-pgdg Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 7FCC7D46ACCC4CF8
  Fetching .debs for libicu-dev
    Reading package lists...
    Building dependency tree...
    The following extra packages will be installed:
      libicu42
    Suggested packages:
      icu-doc
    The following NEW packages will be installed:
      libicu-dev libicu42
    0 upgraded, 2 newly installed, 0 to remove and 93 not upgraded.
    Need to get 10.5MB of archives.
    After this operation, 32.4MB of additional disk space will be used.
    Get:1 http://archive.ubuntu.com/ubuntu/ lucid-security/main libicu42 4.2.1-3ubuntu0.10.04.1 [7607kB]
    Get:2 http://archive.ubuntu.com/ubuntu/ lucid-security/main libicu-dev 4.2.1-3ubuntu0.10.04.1 [2885kB]
    Fetched 10.5MB in 0s (24.3MB/s)
    Download complete and in download only mode
  Installing libicu-dev_4.2.1-3ubuntu0.10.04.1_amd64.deb
  Installing libicu42_4.2.1-3ubuntu0.10.04.1_amd64.deb
  Writing profile script
/tmp/buildpackKE57r/bin/compile: line 78: /LIBRARY_PATH: Read-only file system
ERROR: Build failed, exited 1
hammady@hossams-air~/Workspace/herokutest$ [A