I found this on a dedicated BlackBerry forum:
I just wish to add that if you don't know how start the Application Loader (at step 3)on the new versions of the BlackBerry Desktop Software, navigate to:
C:\Program Files\Common Files\Research In Motion\AppLoader
double-click the file named "Loader.exe"
my blackberry 7290 won't work anymore.everytime i open it the screen would only say TCU exception reset. . how will i fix this