This Podcast with Qigong Research Vice President Tom Rogers should help reassure you on the safety of Qigong.

http://www.qigonginstitute.org/html/whatsnew.php

You should be fine with Spring Forest Qigong.

Yes Qigong can potentially be dangerous if the practice is not balanced. That is why it is important to have a good system.

Some people read a book and start packing chi into a particular body parts and get into trouble. Also, there are fundamentals that need to be worked on before moving into advanced practices. The key to choosing a system is to view what the results that senior practioners are getting.