diff --git a/debian/libghc6-cabal-dev.postinst b/debian/libghc6-cabal-dev.postinst
index fa5fc562dc04a408a03f1aa2fe9f40e97ce9cda9..dbf415185580f2398c628bb50c72080bff119fd8 100644
--- a/debian/libghc6-cabal-dev.postinst
+++ b/debian/libghc6-cabal-dev.postinst
@@ -19,7 +19,8 @@ set -e
 
 case "$1" in
     configure)
-        source /usr/share/doc/libghc6-cabal-dev/register.sh
+        chmod +x /usr/share/doc/libghc6-cabal-dev/register.sh
+        /usr/share/doc/libghc6-cabal-dev/register.sh
     ;;
 
     abort-upgrade|abort-remove|abort-deconfigure)
diff --git a/debian/libghc6-cabal-dev.prerm b/debian/libghc6-cabal-dev.prerm
index 92d19be4d4f9362890da91a900214744a179db93..1a83b4ce6e2685fac3f64d5dab668ead537ba6c6 100644
--- a/debian/libghc6-cabal-dev.prerm
+++ b/debian/libghc6-cabal-dev.prerm
@@ -19,7 +19,8 @@ set -e
 
 case "$1" in
     remove|upgrade|deconfigure)
-        source /usr/share/doc/libghc6-cabal-dev/unregister.sh
+        chmod +x /usr/share/doc/libghc6-cabal-dev/unregister.sh
+        /usr/share/doc/libghc6-cabal-dev/unregister.sh
         rm -f /usr/lib/haskell-packages/ghc6/lib/Cabal-0.5/HSCabal*.o
 
 #       install-info --quiet --remove /usr/info/missingh.info.gz