This is called at the beginning of the delete process prior to the actual delete.
Edit Issue screen
public String ucPreDelete ( String probId, // the problem id
Connection dbconn, // a Connection
SesameSession session, // current session
ProblemFormParam pfp ) // values from the form
It can return an error message to halt the process with an error condition, and its typical use is to prevent the deletion of an issue if a child issue exists.