Some readers have unfortunately experienced problems to launch Rosetta-dependent applications after having installed Quicktime 7.2.
The problem is in fact due to the beta version of Java 6 massively installed by users and developers, priori to Quicktime update.
To solve the problem with Rosetta, one simply needs to uninstall Java 6 and come back to the previous version Java 5.
All details are provided in the Apple forums.
An update for Quicktime or beta Java 6 should fix the issue in a near future.
[translation by Linathael]