The Problems view is a default Eclipse view that displays system-generated errors, warnings, or information associated with a resource. For example, if a receive step in your process does not have a subscription document specified, the error is automatically logged in this view. The Problems view also displays errors and warnings generated by Simulation (in the Process Simulation perspective).
The Problems view opens by default in the Process Development perspective. If you close the Problems view and want to reopen it, or if you want to open it in another perspective, go to Window > Show View > Problems.