Russ,
Are you able to play the files from your computer? As Ted has mentioned, the SqueezeBox software has the SOX downsampler built-in. It should automatically play any file.
I only have a few files above 24/96 but my unit has no trouble playing them. Are you trying to stream the files over wi-fi or hardwired with Ethernet? Have you installed any of the Soundcheck software mods? That might interfere with the SOX program.