In a Linux graphical environment, if an alphabetic character is edited in a numeric entry-field, runtime shows error message ACCEPT REQUIRED. After that, runtime freezes and it's impossible to work with the application.
This message is quite common and it's usually caused by the working storage variable the entry-field has associated with it. Check the version of the runtime using "runcbl -vv". If it shows that release is 8.1.2, the best thing to start with is to upgrade to release 22.214.171.124.