diff --git a/ci/scripts/install.sh b/ci/scripts/install.sh
index 41f5012660a378865896f120b97ced08eb33b4b9..cacae9585cca70c5c76291532b6989b879fdff32 100644
--- a/ci/scripts/install.sh
+++ b/ci/scripts/install.sh
@@ -8,12 +8,12 @@ if [ $# -ne 2 ]; then
 fi
 
 if [ ! -d "$1" ]; then
-    echo "Folder $1 does not exist."
+    echo "Build folder $1 does not exist."
     exit 1
 fi 
 
-if [ ! -d "$2" ]; then
-    echo "Folder $2 does not exist."
+if [ -d "$2" ]; then
+    echo "Install folder $2 already exists."
     exit 1
 fi 
 
@@ -21,6 +21,7 @@ BUILD_FOLDER="$1"
 INSTALL_FOLDER="$2"
 
 cd $BUILD_FOLDER
+touch $INSTALL_FOLDER
 make install
 export PYTHONPATH=$INSTALL_FOLDER
 python -c 'import hysop; print hysop'
diff --git a/src/hysop++/src/fft/fftw3.h b/src/hysop++/src/fft/fftw3.h
index 56c5c1eacbb02d04ea5c0c7503954acb6ef59901..e71a137c559c0c0d8260bf6324b5e1b195934e01 100644
--- a/src/hysop++/src/fft/fftw3.h
+++ b/src/hysop++/src/fft/fftw3.h
@@ -3,6 +3,7 @@
 #define HYSOP_FFTW3_H
 
 #include <complex>
+#include <stdexcept>
 #include <fftw3.h>
 
 #ifdef HAS_QUADMATHS