Unable to install Outlook plugin - not a valid office Add-in error

I have just signed up and am on Enterprise trial. I also purchased the outlook mail plugin.

I am using Windows 7 64 bit, and Microsoft Outlook 2010 64 bit.

The plug-in was downloaded successfully, and installed correctly. No errors shown.

But when I go into Outlook, I do not see the Zohocrm bar. When I go to the Add-ins, I do not see Zoho crm plug-in at all. When I click on GO for manual addition of the DLL, as mentioned in the help, I get the

c:\users\vinai\appdata\roaming\zoho\zohocrm\zohocrmoladdin.dll is not a valid office add-in error.

Please advice how to fix it asap.

My email is vinai@pmchamp.com, and contact is +65 9877-3485.

Thanks,
Vinai