If you load the file called E0622701 etc. and look at the coordinates of the drawing after import, you will see that there are some ridiculously large coordinates in the file. If you open the Selection Explorer and look at the list of objects that are listed for the imported file, you will also see that the first few items in the list have some ridiculous elevation values (positive and negative values in the Gazillions). This is the problem with the file.
So what I do is scroll down the list in the selection explorer until I find the Text or Point Objects and then take a look at the coordinates of those and then do a Zoom Precise to one of those coordinates and then add 10,10 N and E of the item to generate a 10x10 window on the data that is good. Then I zoom out from there until I get all of the drawing data that is "Good Coordinates" on screen. Now do a CTRL A to select all and the hold the CTRL key down and deselect the good data and then CTRL D to delete the data that is out in Autodesk Hyperspace / Galaxy somewhere ....
Now zoom extents in the plan view and you should have eliminated the wild and wacky Autodesk Galactic residue.
Now you need to determine if there is any 3D objects in the file that you want to retain the Elevations on - and if everything is either 0 or in the Stratosphere or in Hades then you can simply change elevation on all data to undefined. If there is good 3D data in the file that you want to keep then you should do an advanced select on all data in Hades ( Anything below 0) or in the Stratosphere (anything above the max elevation for the project - if you find a contour or spot elevation - just add 1000 to that and that will be good enough), and change the elevation on those to Undefined to bring it back into the real world and then you should be god to go.
I did this - it took a couple of minutes but there is life in this DWG and once you fix the crazy coordinates it should work just fine. Autodesk Software must know that people don't work in those places so they must have some smarts that excludes those values and assumes they are 0 - why they don't just have an undefined value or use 0 I will never understand ....
Let me know if this helps - if not I can send you your fixed files back as I have them now
Alan