Why can't I import .pdf, .dwg or .dxf files?

This is very troubling.  I work with Autocad files, currently Acad 2010 is being used in the office.

I'm trying to import a siteplan for coloring, and I can't get the darn thing into X5.  I import as a .pdf (created from Autocad) and I get a "file is corrupt" error.  I'm used to that in X3, with Adobe upgrading the .pdf standard, but X5 should be able to read these files, right?  This is the solution I'd prefer as it would be a one-step process, all lineweights and text spacing, etc. shouldn't change from the original file.  At least one would think so.

If I import as a .dwg or .dxf, I get the expected dialogs, but after the font-matching dialog, CorelDraw shuts down with no explanation!  Poof!  I've gone back 15 years saved the .dxf as release 14 and still, poof!  

I'm going to have to use X3 until this gets resolved...