FreeImage_OpenMultiBitmap Not working on iOS

Hi Forum,

I am trying to use FreeImage on iOS. This is what I did:

string filePath = ofxiPhoneGetDocumentsDirectory() + “filename3.gif”;

FIMULTIBITMAP *multi = FreeImage_OpenMultiBitmap(FIF_GIF, filePath.c_str(), TRUE, FALSE);

I always get multi as a null pointer.

ps. ofxiPhoneGetDocumentsDirectory() is:
/var/mobile/Containers/Data/Application/APPLICATION_ID/Documents/, which should be ok to create files.

Any ideas?