PPM login screen was appeared? or login screen was blank screen?
If you get blank screen after login PPM, your PPM Home Page maybe corrupted.
Please check other page can be appeared.
For example, please try to display project list by following steps.
1. specify project list URL like as below into your browser URL field
http://<your PPM server>/niku/nu#action:mainnav.work&classCode=project
2. click enter key. It will display project list directly.
If project list is appeared completely, your PPM Home Page maybe corrupted.
Regards,
Shoichi