Bugfix: headless mode

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@4572 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/settings/FileSetting.java

@@ -64,6 +64,9 @@ public class FileSetting extends Setting
 		catch (HeadlessException e) {
 			return null;
 		}
+		catch (Error e) {
+			return null;
+		}
 	}
     
 	private boolean validFile;