More details will help. What is giving you trouble?
PPT Version -
32 or 64 bit -
Version of Presenter you are trying to install -
Be sure you are installing the same version of Presenter (32 bit or 64 bit) as your version of PPT. Discussed here: http://forums.adobe.com/message/5465181#5465181
Be sure that your version of PPT is supported: http://www.adobe.com/products/presenter/tech-specs.html