cast COM Exception when creating VPN

I have a webApp written in asp.net that creates VPN connection per user request (uses F5 Networks Components. It works fine on windows XP and vista, however, I get the following error when I run it on a server 2008 VMware:
12/17/2009 16:46:16 VPN: Exception caught opening session: InvalidCastException: Unable to cast COM object of type 'APPCTRLLib.AppTunnelExClass' to interface type 'APPCTRLLib.IAppTunnelExConnectionSettings'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{BA82B157-1C6E-4F7E-AB7D-2654282C25E4}' failed due to the following error: No such interface supported (Exception from HRESULT: 0x80004002 (E_NOINTERFACE)).
12/17/2009 16:46:16 Exception caught while polling: InvalidCastException: Unable to cast object of type 'System.EventArgs' to type 'System.Timers.ElapsedEventArgs'.

I done some googling, it seems that there is a problem in the windows registery.
C:\windows\system32 > regsvr32.exe /u actxprxy.dll
and then register it again C:\windows\system32 > regsvr32.exe actxprxy.dll, didnot work for me as it is suggested in http://social.msdn.microsoft.com/Forums/en-US/sqltools/thread/d5d3e5fc-d8ce-4f42-b7ea-9bbbb7756a20

any ideas?

thanks