Comming up incompatible version when I try and open blocks on this site. I have autocad 2000?

DWG or DXF? If it is a DXF, you can open the drawing in Notepad and find if there is AC****, you can refer to the following details and find which drawing version it is. AC1015 - DWG from AutoCAD 2000/2000i/2002 (or LT, Map or relative Desktop version). AC1018 - DWG from AutoCAD 2004/2005/2006 (or other product in the "2004", "2005" or "2006" family). AC1021 - DWG  from AutoCAD 2007/2008/2009 (or other product of the "2007", "2008" and "2009" families). AC1024 - DWG from AutoCAD 2010 (or other product of the "2010" family). If you got the 'incompatible' message, it may be a higher version than 2000. You can try the version conversion feature of this software and get 2000 version draiwng for your AutoCAD:http://www.autodwg.com/DWG_DXF_Converter/Hope this helps.AmerieWhite2009-06-07 16:45:01

Hi,
 
It's dwg file, will download and see if it opens it.
 
Cheers,

I just got a try and found that DWG can also be open up in Notepad although there are lots of messy, but there is "AC****" there that you can find in first line first word.
AmerieWhite2009-06-08 03:01:17

You don't need Notepad nor any third-party application. Autodesk DWG TrueView 2010 (see the Download page here) opens any DWG file and saves it to an older version of DWG (incl. DWG2000).
 
Using non-Autodesk tools for DWG conversion results in unreliable files in a non-genuine DWG file format.