Implementing the HIDictionaryWinsowShow function and receiving an error: Carbon window attributes could not be obtained

Question

I want to add a dictionary service to my application, so I am implementing HIDictioanryWindowShow (). here is my code

Range CFRange = DCSGetTermRangeInString (string NULL, (__ bridge CFStringRef), 0);

CTFontRef font =CTFontCreateWithName((__bridge CFStringRef)string, 0.0, NULL); CGFloat x= [_window frame].size.width/3; CGFloat y = [_window frame].size.height/2; 

HIDictionaryWindowShow (NULL, (__bridge CFStringRef) string, range, font, CGPointMake (x, y), YES, NULL);

and when I launch my application, an error occurs: the attributes of the Carbon window cannot be obtained. Carbon windows could not be obtained. Failed to get window modality: error = -5600

Please help me! thanks!