I'm not with Laminar Research, just a fellow simmer in the UK.
I think we're going to need a tad more information if we are going to try and help you with this one, so some initial questions:-
1. What version of XP11 are you using i.e. 11.30 etc.
2. Is your copy of XP11 a genuine digital download from LR, a DVD set from LR, or was it sourced from elsewhere i.e. a third party?
3. What external apps are you referring to?