Virus vst hangs cubase 5.5.1

  • Hi guys, just wondering if you can help me

    When returning to a project after working on it for some time the virus VST seems to hang when i click the 'e' in cubase's instrument list. this doesn't happen from a default project or if i delete all the tracks in the project?

    im using xp pro
    cubase 5.1.1