Nasty one! Sounds like some old software - or not-so-good software. If you really must have the program and it really won't let you continue the install without loading QT v2 (if it will let you continue without loading v2 then should be no problem as v4 is almost certainly "backwards compatible") then I would suggest:-
Make sure you have a source for QT v4 (from the web or the program it originally came with) and delete v4.
Now load your "new" software, complete with QT v2, and run it to check it out.
Finally load v4 again and everything
should be okay. The worst is that your "new" software may not work with v4 - but I doubt it.
Of course the best solution would be to get the latest release of the package you want to use after ensuring that it uses v4 or above!
Good luck
