ofxTrueTypeFontUC in class

Hello friends
I got a problem when using ofxTrueTypeFontUC in my own class:
I defined a class named CMyInvestor, I want ‘make’ a image inserting a Chinese string into when CMyInvestor object setup:

// CMyInvestor.h

class CMyInvestor
{

ofImgae         imgBlank;
ofxXmlSettings  xml;
string          strText;
ofFbo           fbo;
ofTexutre       texPic;

void init()
{

 imgBlank.loadImage("blank.png");
 xml.loadFile("text.xml");
 strText = xml.getValue("text","");

 fbo.allocate(1280,720)
 fbo.begin();
 imgBlank.draw(0,0);
 drawChineseString(strText);
 fbo.end();
 texPic = fbo.getTextureReference();

}
}

// ofApp.h
static ofxTrueTypeFontUC ttfuc;
static void drawChineseString(string _s)
{
ttfuc.drawString(util::ofxTrueTypeFontUC::convToWString(_s),100,100);
}

CMyInvestor inves;

// ofApp.cpp

void ofApp::setup()
{
ttfuc.loadFont(“chn.ttf”,45);
inves.init();
}

when process in inves.init(),oF occurs error:
ofxTrueTypeFontUC::drawString - Error : font not allocated

can anyone help me ?