Issue with sapssoext on 64 bit amd 2008 r2 windows server

We like to use SingleSignOn between a Netweaver 702 and a third party application writen in .net c# 4.0. We followed the steps as described in paper "Enabling Single Sign On Between Enterprise portal and non-sap applications" written by Md Ansar Hussain on 30-Oct-2008.

At runtime, we receive a COM exception 80040154 Class not registerd(Exception from HRESULT: 0x800401554 (REDB_E_CLASSNOTREG))

We have downloaded and installed the latest version of sapssoext.dll and seculib.dll. We successfully registered sapssoext.dll using regsvr32. The files are store in system32 directory.

Are there any specific steps where we have to follow to get the application running on a 64 bit machine?

Thank you for your help.

Peter