diff --git a/install_minimal/DoctrineMigrations/Version20110711161043.php b/install_minimal/DoctrineMigrations/Version20110711161043.php
index 4a0bed554..10821f9b2 100644
--- a/install_minimal/DoctrineMigrations/Version20110711161043.php
+++ b/install_minimal/DoctrineMigrations/Version20110711161043.php
@@ -27,7 +27,15 @@ class Version20110711161043 extends AbstractMigration
         $cc_files->addColumn('directory', 'integer', array('notnull' => 0, 'default'=> NULL));
 
         $cc_files->addNamedForeignKeyConstraint('cc_music_dirs_folder_fkey', $cc_music_dirs, array('directory'), array('id'), array('onDelete' => 'CASCADE'));
-
+        
+        // before 3) we have to delete all entries in cc_schedule with file_id that are not in cc_file table
+        $this->_addSql("DELETE FROM cc_schedule WHERE cc_schedule.id IN(
+                        SELECT cc_schedule.id
+                        FROM cc_schedule
+                        LEFT JOIN cc_files
+                        ON cc_schedule.file_id = cc_files.id
+                        WHERE cc_files.id IS NULL)");
+        
         /* 3) create a foreign key relationship from cc_schedule to cc_files */
         $cc_schedule = $schema->getTable('cc_schedule');
         $cc_schedule->addNamedForeignKeyConstraint('cc_files_folder_fkey', $cc_files, array('file_id'), array('id'), array('onDelete' => 'CASCADE'));
diff --git a/install_minimal/airtime-install b/install_minimal/airtime-install
index cc104e775..d1e5afa67 100755
--- a/install_minimal/airtime-install
+++ b/install_minimal/airtime-install
@@ -1,5 +1,11 @@
 #!/bin/bash
 
+DEB=$(dpkg -s airtime 2> /dev/null | grep Status)
+if [[ "$DEB" = "Status: install ok installed" ]]; then
+    echo -e "\nDebian package of Airtime detected. Please use the debian package to upgrade.\n"
+    exit 1
+fi
+
 echo -e "\n******************************** Install Begin *********************************"
 
 # Absolute path to this script
@@ -8,6 +14,7 @@ SCRIPT=`readlink -f $0`
 SCRIPTPATH=`dirname $SCRIPT`
 
 VIRTUAL_ENV_DIR="/usr/lib/airtime/airtime_virtualenv"
+VIRTUAL_ENV_SHARE="/usr/share/python-virtualenv/"
 if [ ! -d "$VIRTUAL_ENV_DIR" ]; then
     echo -e "\n*** Creating Virtualenv for Airtime ***"
     EXTRAOPTION=$(virtualenv --help | grep extra-search-dir)
@@ -15,9 +22,11 @@ if [ ! -d "$VIRTUAL_ENV_DIR" ]; then
     if [ "$?" -eq "0" ]; then
         sudo virtualenv --extra-search-dir=${SCRIPTPATH}/3rd_party --no-site-package -p /usr/bin/python2.6 /usr/lib/airtime/airtime_virtualenv
     else
-        # copy distibute-0.6.10.tar.gz to /usr/share/python-virtualenv/
+        # copy distribute-0.6.10.tar.gz to /usr/share/python-virtualenv/
         # this is due to the bug in virtualenv 1.4.9
-        cp ${SCRIPTPATH}/3rd_party/distribute-0.6.10.tar.gz /usr/share/python-virtualenv/ 
+        if [ -d "$VIRTUAL_ENV_SHARE" ]; then
+            cp ${SCRIPTPATH}/3rd_party/distribute-0.6.10.tar.gz /usr/share/python-virtualenv/
+        fi
         sudo virtualenv --no-site-package -p /usr/bin/python2.6 /usr/lib/airtime/airtime_virtualenv
     fi