Sometimes it may happen that you navigate to one of the extension backend pages and see it blank. It can be caused by one of the following reasons:
1. The extension output is disabled. In this case, navigate to System > Configuration > Advanced > Disable Modules Output and check if the extension output is disabled there.
2. Magento can't find the appropriate template file to display the requested page or file permissions are not enough for Magento to read the template. In this case you should check file permissions set to every extension template file which are most likely stored into /app/design/adminhtml/default/default/template/...
3. A fatal error appeared during building up the page. To find out what is the error message, you can turn on Magento exception logging, request this page one more time and look into the exception log.