Problem with Plugins

I have a problem with my plugins. i am using Cubase 4.5 on Windows 7 64bit. i have installed a few plugins namely Amplitude and it installed fine and appears in the inserts list and opens correctly but when i right click an audio file and go to the plugins menu it does not appear. has anyone else had this problem. please help.

thanks

I have fixed the problem now. For anyone who ever has this problem again. The plug-ins started showing when I updated with the 32bit version rather than the 64 (and yes am definitely running a 64bit version of Windows 7).