Fixed logic when ParaBreak is null

Fixed logic when PDF is open

PROMS/Volian.Print.Library/Pagination.cs

@@ -949,7 +949,7 @@ namespace Volian.Print.Library
 					}
 				}
 			}
-			if (paraBreak.PageBreakReason == null)
+			if (paraBreak != null && paraBreak.PageBreakReason == null)
 				paraBreak.PageBreakReason = "Rest of Step fits at 6 LPI";
 			ProfileTimer.Pop(profileDepth);
 		}