LDataBrowser in Xcode UB

I am trying to use PowerPlant in Xcode. One problem I have is with
LDataBrowser I get a link error:

__ZThn136_N12LDataBrowser11ObeyCommandElPv
__ZThn136_N12LDataBrowser12DontBeTargetEv
__ZThn136_N12LDataBrowser14HandleKeyPressERK11EventRecord
__ZThn136_N12LDataBrowser17FindCommandStatusElRhS0_RtPh
__ZThn136_N12LDataBrowser8BeTargetEv
__ZThn136_N12LDataBrowserD0Ev
__ZThn136_N12LDataBrowserD1Ev

Although c++flit indicates that the object code exists.

% nm -a libPowerPlantD.a | grep 6_N12LDataBrowser11ObeyCommandE | c+
+filt
000029be S non-virtual thunk to LDataBrowser::ObeyCommand(long, void*)
% echo __ZThn136_N12LDataBrowserD0Ev | c++filt
non-virtual thunk to LDataBrowser::ObeyCommand(long, void*)

Although, I have not see "non-virtual thunk to ".  My usage of
LDataBrowser is below:

class MDLDataBrowserClient {
public:
  virtual	Boolean DLDBCompareItems(
                  const PP_PowerPlant::LDataBrowserItem * inItemOne,
                  const PP_PowerPlant::LDataBrowserItem * inItemTwo,
                  DataBrowserPropertyID inSortProperty);
};

class CDLDataBrowser : public PP_PowerPlant::LDataBrowser {
  MDLDataBrowserClient* mClient;

public:
    	enum { class_ID = FOUR_CHAR_CODE('DLDB') };

	CDLDataBrowser(PP_PowerPlant::LStream* inStream );
	virtual ~CDLDataBrowser();
  virtual void SetClient(MDLDataBrowserClient*);

  Boolean mAllowSort;

  void FinishCreateSelf();

  void ItemNotification(PP_PowerPlant::LDataBrowserItem* inItem,
DataBrowserItemNotification inMessage);
  Boolean AllowBeTarget(PP_PowerPlant::LCommander*		inNewTarget);
  Boolean AllowDontBeTarget(PP_PowerPlant::LCommander*		inNewTarget);


	virtual	Boolean CompareItems(
								const PP_PowerPlant::LDataBrowserItem *	inItemOne,
								const PP_PowerPlant::LDataBrowserItem *	inItemTwo,
								DataBrowserPropertyID		inSortProperty);
};

Any ideas why this will not link?

Regards, Brian Ray