diff --git a/install_toolchain.sh b/install_toolchain.sh
index 805f761..9f32df8 100755
--- a/install_toolchain.sh
+++ b/install_toolchain.sh
@@ -16,17 +16,17 @@ export SRC_POOL=${HOME}/src
 export WORKDIR_BASE=${HOME}/work
 
 #PREFIX=$HOME/bin/local
-PREFIX=/opt/amtopt/autotools/local
+PREFIX=${PREFIX:=/opt/amtopt/autotools/local}
 MAKEOPTS="-j4"
 
 
 
-module load compiler/gnu/4.4.3
+#module load compiler/gnu/4.4.3
 
 M4_VERSION=1.4.15
-BISON_VERSION=2.4.2
-LIBTOOL_VERSION=2.2.10
-AUTOCONF_VERSION=2.65
+BISON_VERSION=2.4.3
+LIBTOOL_VERSION=2.4
+AUTOCONF_VERSION=2.68
 AUTOMAKE_VERSION=1.11.1
 
 
@@ -67,7 +67,7 @@ sit_auto_install
 
 # install autoconf 
 P=autoconf-${AUTOCONF_VERSION}
-A=${P}.tar.gz
+A=${P}.tar.bz2
 sit_auto_install
 
 export PATH=$PREFIX/bin:$PATH