93 Photo Street uses the Java Advanced Imaging libraries which Apple has unfortunately licensed in such a way that they can not be bundled with OS X applications. This is not true of the same libraries for Windows, and is very annoying.
Even more annoying is the fact that Apple's installer for the libraries stopped working on some versions of OS X 10.3, somewhere after 10.3.8 was released.
The primary symptom of this failure is 93 Photo Street's display of a dialog asking you to install the libraries, even after the installer has been run.
Try Apple's installer, which is linked from the 93 Photo Street dialog. If it works on your machine, you will not see the dialog again when you restart 93 Photo Street and you can skip the next steps.
Download this archive file: JAI_Libs.tgz
While 93 Photo Street is not running, double click the JAI_Libs.tgz archive and move the four resulting files into /System/Library/Java/Extensions/
Those files provide the Java Advanced Imaging libraries, so now when you start 93 Photo Street it should not complain.