I think the issue is that from the standby you cannot connect to the primary. Please logon to the standby server and try and connect to the primary via sql*net. Likely you will get an error, which is why you are seeing this in DG broker.
Can you try following senario and pste here results:
1. Add tnsnames.ora QA112PRG, QA112STB on both server (primary and standby).
2. If you are writing QA112PRG, QA112STB desriptions with hostname you can add servernames and ips to */etc/hosts* file.
3. Try on both server : tnsping QA112PRG; tnsping QA112STB
4. Set StandbyFileManagement parameter set 'AUTO' , this help datafile management automatically .
5. Watch my video : http://www.mahir-quluzade.com/2012/01/overview-data-guard-configuration.html