Hi. I think that you should see what the DRC rules are for minimum spacing in each metal layer, and then I think there is a way in IC Station that you can set up both your autorouter and your manual router to follow those minimum spacing rules so that it will not violate them. To fix DRC errors, you just need to go through them one by one and manually fix each one. For example, if you have too little spacing between two metal3 lines, then you need to manually move them apart.
As you run DRC on layout using calibre it show up a RVE in that it says what are the DRC erros and there is description in RVE to solve those errors try to understand the DRC rule and what are the threshold value to avoid those. and sorry to say that i dont regarding overflow in IC station.
Thanks & Regards