LabVIEW call CVI daisy chained DLL fail

Hi

    Daisy chained DLL: DLL A and DLL B, DLL A use LoadLibrary to load DLL B.

   I have created a dll in Labwindows CVI. In this dll I dynamically call another dll using LoadLibrary function. This dll works fine when I call DLLA in labwindows cvi and I get right return value(the return value was computed by DLL B).

   When using labview , the call Iibrary funtion node run smoothly and the error out with no error, but the return value always 0, sames that labview load DLL A successfully , but DLL A can't load DLL B using LoadLibrary function so that return value always 0. Any idea why?(DLLA and DLLB under same directory)

   for example; I have created dllA.dll in cvi. In dllA.c I have code like this

        dll_handle = LoadLibrary ("DLLB.dll");

       if(dll_handle == NULL) {

            MessagePopup ("ERROR", "LIB2.DLL Load Error"); return -49;

         }

       return DLLB_FuncGetValue();

using labwindows I can call dllA.dll and it successfully loads DLLB.dll.