Hi again,
Yep - your non-www and www pages are both resolving... e.g. http://cheaptubes.com/ and http://www.cheaptubes.com/ bring up the same content. Also, http://cheaptubes.com/default.htm and http://www.cheaptubes.com/default.htm is also a duplicate of the home page.
Internally, I am seeing the same thing, e.g. http://www.cheaptubes.com/carbon-nanotubes-prices.htm and http://cheaptubes.com/carbon-nanotubes-prices.htm - same page, one on the www subdomain ("www." is a subdomain like any other, just with an extremely common name) and one just sitting on the root.
The solution here is either to 301 redirect the non-www version of the site to the www version for every page, or to use the canonical tag to point from the non-preferred versions to the "canonical" versions. More information on this is available here.
You also have a situation where upper-case URLs will resolve as well as lower case ones, e.g. http://www.cheaptubes.com/SWNTs.htm and http://www.cheaptubes.com/swnts.htm (as well as http://cheaptubes.com/swnts.htm!).
URLs should only be allowed to resolve with one case, preferably lower. The upper / mixed case should 301 redirect to the proper version.
Essentially, the "two versions of the site" issue is the biggest problem, with all pages being available on at least two URLs - one with www and one without. There are other tidiness issues like /default.htm bringing up the home page as well.
Does this make sense? Let me know if this is not clear.
Best,
Jane