Hi Diego,

Please note that the 32-bit DLL could not be loaded on 64-bit IE, if it is a 32-bit DLL, please make sure you are run 32-bit IE. Here is a solution to open 32-bit IE, please give a try.

Step1: In the registry , change the value of
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\TabProcGrowth to
the value greater than 0.
Step 2: Restart the IE.
For more details please refer to:
http://support.microsoft.com/kb/2716529

If there is still any issue, please refer to article below to solve it.
http://support.appeon.com/index.php?/Knowledgebase/Article/View/40/15/how-to-figure-out-the-error-could-not-register-the-file-dll--or-fail-to-load-dlls-when-running-the-web-application

Regards,
ZhaoKai