RE: What are the errors encountered while testing an a...
We can't specifically say that. It depends on the stability of the application. They might be Navigational blocks, exceptions, non -functionality of Links, buttons, pages, environmental issues...etc...
RE: What are the errors encountered while testing an application manually or using automated tool like Testdirector,Winrunner.
Automated testing is difficult when the product is changing. It is generally much easier early on to test the product manually. As the product procedes, and a new version of the product comes out, automation pays off. Sometimes small modifications have to be made to the tests for the new version, but it is usually realatively easy, if it is documented properly. Unfortunately, most of the test failures don't turn out to be bugs, they can be created by the automation itself, or the bugs are difficult or impossible to reproduce ie. race conditions.
