PPC-only preference panes don’t work on the new Intel Macs, because System Preferences launches in Intel-only mode. Sadly, this affects PathSnagger. A workaround, documented at MacFixIt, is to force the System Preferences application to run under Rosetta:
You can, however, force the System Preferences application to run under Rosetta (navigate to /Applications, click on the System Preferences icon, go to Get Info and check “Run with Rosetta”) in order to access such Preference panes on your Intel-based Mac.
MacFixIt reader Stéphane has put this workaround into practice, and notes: “In this case, the native will not run any more, but it’s a workaround. You can probably make a copy of the ‘System Preferences’ application, for PPC Prefpanes only; and leave the original for the native ones.”
If you don’t want to do this, the alternative involves editing the ~/Library/Preferences/com.bergenstreetsoftware.PathSnagger.plist file manually.
The next release of PathSnagger will be a Universal Binary, so this shouldn’t be a problem at that point.