A few notes first, I recommend that you update to the latest Eagle version and use the built-in CAM files since they do resolve a few problems that were present in the past. I can't remember the details but generally it is better.
2層 CAM ファイル
4層 CAM ファイル
Similarly, for the DRU files, they were taken down since they caused customers some confusion. For example, the minimum drill hole diameter is 0.3mm but actually you can have 0.2mm drill holes, they just cost extra. So, is that a DRU violation or not? It depends on the customer's budget.
DRU files (Eagle 向け） （最新のeagle バージョン で開けるのはお勧めです）