Facepunch decided to rename the oilrig monuments in this month's update, so DynamicPVP is no longer able to recognize them:

• OilrigAI -> oilrig_2
• OilrigAI2 -> oilrig_1

Please provide more details... on my server (just started) I see the following:

[Dynamic PVP] Trying create zone: Oil Rig(2020255810 | (2806.87, 0.00, 1122.68)) (Radius: 100m) (Duration: -1s).
[Dynamic PVP] Created zone(2020255810 | Oil Rig) (Dome,Mapping).
[Dynamic PVP] Trying create zone: Large Oil Rig(2020260849 | (2715.44, 0.00, 2802.11)) (Radius: 100m) (Duration: -1s).
[Dynamic PVP] Created zone(2020260849 | Large Oil Rig) (Dome,Mapping).​

You had some code looking at the old prefab names. I've added the new ones alongside them here:

                switch (landmarkInfo.name)
                {
                    case "oilrig_2":
                    case "OilrigAI":
                        _oilRigPosition = landmarkInfo.transform.position;
                        break;
                    case "oilrig_1":
                    case "OilrigAI2":
                        _largeOilRigPosition = landmarkInfo.transform.position;
                        break;
                    case "assets/bundled/prefabs/autospawn/monument/harbor/harbor_1.prefab":
                        monumentName += " A";
                        break;
                    case "assets/bundled/prefabs/autospawn/monument/harbor/harbor_2.prefab":
                        monumentName += " B";
                        break;
                    //case "assets/bundled/prefabs/autospawn/monument/harbor/fishing_village_b.prefab": monumentName += " A"; break;
                    //case "assets/bundled/prefabs/autospawn/monument/harbor/fishing_village_c.prefab": monumentName += " B"; break;
                }​

FYI, 4.2.19 seems to have got the new prefab names backwards.