diff --git a/C4/Auth.pm b/C4/Auth.pm
index df0cf31425..b531ab4a6a 100644
--- a/C4/Auth.pm
+++ b/C4/Auth.pm
@@ -23,6 +23,8 @@ use Carp qw( croak );
 
 use Digest::MD5 qw( md5_base64 );
 use CGI::Session;
+use URI;
+use URI::QueryParam;
 
 use C4::Context;
 use C4::Templates;    # to get the template
diff --git a/C4/Auth_with_cas.pm b/C4/Auth_with_cas.pm
index 5becd96fdc..3817a69d70 100644
--- a/C4/Auth_with_cas.pm
+++ b/C4/Auth_with_cas.pm
@@ -25,6 +25,7 @@ use Koha::AuthUtils qw( get_script_name );
 use Authen::CAS::Client;
 use CGI qw ( -utf8 );
 use YAML::XS;
+use URI::Escape;
 
 use Koha::Logger;
 
diff --git a/opac/opac-user.pl b/opac/opac-user.pl
index 6feb144e50..e610cabc2a 100755
--- a/opac/opac-user.pl
+++ b/opac/opac-user.pl
@@ -57,8 +57,10 @@ my $query = CGI->new;
 
 # CAS single logout handling
 # Will print header and exit
-require C4::Auth_with_cas;
-C4::Context->preference('casAuthentication') and C4::Auth_with_cas::logout_if_required($query);
+if ( C4::Context->preference('casAuthentication') ) {
+    require C4::Auth_with_cas;
+    C4::Auth_with_cas::logout_if_required($query);
+}
 
 my ( $template, $borrowernumber, $cookie ) = get_template_and_user(
     {