I'm trying to access the property "CurrentTrack" from "org.bansheeproject.Banshee.PlayerEngine"

Here's my code:
Code:
GHashTable *map = NULL;
DBusGProxy *property = 
dbus_g_proxy_new_for_name (
	conn,"org.bansheeproject.Banshee", 
	"/org/bansheeproject/Banshee/PlayerEngine/",
	"org.freedesktop.DBus.Properties");
dbus_g_proxy_call_with_timeout(property, "Get",
	DBUS_TIMEOUT, &error,
	G_TYPE_STRING, "org.bansheeproject.Banshee.PlayerEngine", 
	G_TYPE_INVALID,
	G_TYPE_STRING, "CurrentTrack",dbus_g_type_get_map
	("GHashTable", G_TYPE_STRING, G_TYPE_VALUE), &map, 
	G_TYPE_INVALID);
I get this error:
process 30644: arguments to dbus_message_new_method_call() were incorrect, assertion "_dbus_check_is_valid_path (path)" failed in file dbus-message.c line 1202.
This is normally a bug in some application using the D-Bus library.

** ERROR **: Out of memory
aborting...
Aborted (core dumped)


conn and error are declared above
GError *error = NULL;
static DBusGConnection *conn = NULL;
conn = dbus_g_bus_get(DBUS_BUS_SESSION,&error);

no other function calls i try to make to banshee work, but using the same code, i can make calls to other dbus's, and i can make call's to the functions in python.

i'm sure it's something dumb.

Thanks
Kevin