Do you output more than one .chm from your project? If you only generate one .chm, you can change the title by choosing Project > Project Settings > General tab and then enter in the correct project title.
If you have more than one output, go to Output > Output Setup and then expand Windows in the Output Setup pod. You can create a window for each .chm output and enter the name in the Window Name field. Then when you are generating your .chm, you can choose the Default Window for your .chm file.