Hi, sorry about your problem, there's a couple of things you could try:
1. Via wap site (recommended)
Open up the browser on your phone and go to m.trutap.com. Click on the download link and install trutap.
2. Install via pc suite
Download Nokia pc suite here, and try using that to install the app: http://europe.nokia.com/A4144905
Hope that helps,
Mark