Dear samiam,
If you look at HTML code of download page (ex.:
www.worldwellnessstore.com/var/turbocach...-mg-60-capsules.html) then you can see
_gaq.push(["_setAccount", "UA-12739668-4"], ["_trackPageview","/4-weightloss-650-mg-60-capsules.html?___store=default&nocache=true&mturbo_dynamic_block=true"]);
It means that the additional parameters is not stripped when Google Analytics generates its code. It is not good.
Which version Magento you use? Do you use any 3rd party module for generating the GA code or you use the default implementation from Magento?