Did you see this at Macfixit? It might have a bearing.
QUOTE
Yesterday we reported that Data Recycler X, a deleted-file recovery tool for Mac OS X, can cause problems by keeping a cached copy of deleted applications and other files.
Upon further investigation, it appears that the problem may not lie in Data Recycler X's tendency to keep multiple applications, but rather on Mac OS X's ability to deal with permissions for multiple copies of the same application.
Say, for instance, that you have installed multiple copies of Macromedia's Flash Player for production work, as well as several old versions of the software. The "Get Info" menu for documents will list all versions, including Classic flavors. The Finder will also list these duplicates under the Open With contextual menu. However, in some cases, the Finder will not allow the user to change the default setting to a particular version of the application. The only workaround is to delete all versions of the application besides the one which you are trying to access.
MacFixIt reader Leo O'Campo writes "Multiple copies of applications should not cause problems with setting the default application to open a document with. [...] As a web developer, many of us have had multiple copies of browsers (most power users do), even different versions, and multiple player applications on our drives for many years. This is common practice in the industry, and never has the Finder arbitrarily, of the blue, reset the 'Open With' default preference to a document and refuse to let the user (with owner privileges) change it."
"My theory is, not to suspect Data Recycler X just because it makes multiple copies [...]. In the case reported yesterday, and mine, the system acted as if the system root user took over that preference, and then would not allow changes. Since this preference is a user feature, the alternative conclusion is the problem is a bug in the Finder or, as I suspect, the privileges."
In some cases, using Apple's Disk Utility to repair permissions will allow the "Open With" default to be changed correctly, for other users, using a utility like BatChmod to set the current user as owner of a given file. For some, this has allowed setting (and sticking) of the default "Open With" application.
