Patch to make errors invoking a class more descriptive.  The errors
only happen when there is a reference to a module that does not exist
or has not been installed.

diff --git a/perl/lib/Wallet/Server.pm b/perl/lib/Wallet/Server.pm
index b0c955c..f4f9f81 100644
--- a/perl/lib/Wallet/Server.pm
+++ b/perl/lib/Wallet/Server.pm
@@ -103,7 +103,7 @@ sub type_mapping {
     if (defined $class) {
         eval "require $class";
         if ($@) {
-            $self->error ($@);
+            print ($self->error ($@));
             return;
         }
     }
@@ -508,10 +508,10 @@ sub checksum {
     }
     my $object = $self->retrieve ($type, $name);
     if (!defined $object) {
-	return;
+    return;
     }
     if (!$self->acl_verify ($object, 'get')) {
-	return;
+    return;
     }
     my $result = $object->checksum($self->{user}, $self->{host});
     $self->error ($object->error) unless defined $result;