Looks like there is one common problem that is causing most scripts to error out. Usually this happens when you database or the db listener is down, but you are saying you can connect to the database via sqlplus.
Take a look at the log file of the concurrent manager and see if you can spot any thing:
/home/Oracle/PROD/inst/apps/PROD_linux/logs/appl/admin/log/adapcctl.txt
Also try stopping all services
adstpall.sh apps/apps
... and then restarting them again adstrtal.sh apps/apps
And see if you still these errors.
Hasan