voltage:
When I compared the code that was showing up on my checkout_success page to the code that google was telling me to copy and paste, I noticed a few small discrepencies. For example this code for the google_conversion_label was different. (I however have no idea what this means.)
Sooo, I turned off the tracking in the admin, and hard coded the sucker in the tpl_main_page for the checkout success page. I have now verified that the code shown is EXACTLY the same code google is telling me to show, but yet, it still fails verification. . . .
The tracking code provided (used) within the module itself works ok and is code that Google authorized quote a while back. Since then they have made some minor adjustments, however, those adjustments have no effect on the tracking code.
As long as you turned the tracking code on from within the Admin (and activated it) then you should not have to manually add any code to your page.
The reason for google not being able to verify the tracking code is more than likely do to the url that you are providing google or some mis configured tracking id number on your end (again, not within the module itself).
The biggest thing I see with people is that many think they have properly setup and configured analytics, when in fact, 95% of the time I get in and find they have not set it up correctly (thus giving errors as you are seeing).
The module itself, once installed, works flawlessly (I'm using it on over 15 sites right now without a problem, and have been for as long as 1.5 years in some cases).
Make sure you exactly and carefully follow the instructions on how to properly give Google the url verification path. The workbook listed in my signature addresses all of these issues and more ... you might find it beneficial to give it a read. I think you'll find a number of issues that are clarified.
:)