I hesitate to report this since it seems more likely that somehow I am wrong, but... I had to make the following changes to allow me to correctly handle variant maps with nested variant maps, i.e. it seems like this logical expression (below) is exactly opposite of what it should be. Prior to this change, I got errors like:
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process 10525: arguments to dbus_message_iter_open_container() were incorrect, assertion "(type == DBUS_TYPE_STRUCT && contained_signature == NULL) || (type == DBUS_TYPE_DICT_ENTRY && contained_signature == NULL) || (type == DBUS_TYPE_VARIANT && contained_signature != NULL) || (type == DBUS_TYPE_ARRAY && contained_signature != NULL)" failed in file dbus-message.c line 2360.
---------------------------------------
and in looking at dbus-message.c from dbus-1.2.14, it seems like my interpretation is correct. I tested with a std::map<std::string,DBus::Variant> which had a std::map<std::string,DBus::Variant> as one of its DBusVariant members.

Darrell


--- dbus-c++/src/message.cpp	2009-09-08 15:20:51.000000000 -0400
+++ dbus-c++-0.5.0/src/message.cpp	2009-09-08 14:38:29.000000000 -0400
@@ -21,9 +21,6 @@
  *
  */
 
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif
 
 #include <dbus-c++/message.h>
 
@@ -350,7 +347,7 @@
 			(
 				(DBusMessageIter *)&(to._iter),
 				from.type(),
-				from.type() == DBUS_TYPE_VARIANT ? NULL : sig,
+				from.type() == DBUS_TYPE_DICT_ENTRY || from.type() == DBUS_TYPE_STRUCT? NULL : sig,
 				(DBusMessageIter *)&(to_container._iter)
 			);