Ok before I get into the doom and gloom part. Did you un-install the trial version before upgrading to the full version? This seems to be a common error when you try to use the full version without uninstalling the trial. This
sounds alot like the issue you are having and it may be the needed fix.
Now onto a gloom scenario. I to would be interested in where you purchased this upgrade from. The 3 links I have found that match MSOCON-BuyUSA have been scams and identity theft. DRI is Digital River Inc.
its a E-Commerce Solution for Software Publishers and the MSOCON is MicroSoft Office Conversion. A quick BBB
check turns up that seem to be a reliable company so the issue would not be with them. So my guess is what ever company you purchased from used Digital River to handle the CC transaction.