Maybe it's late, but after getting my PB 602 today, I could update the firmware, change the logos and few other things but for some reason, I can't make the themes work. I download the zip file, extracted the .pbt file into system/themes directory of the 602 and then select the desired theme in Configuration-Appearance-Theme. But then nothing spectacular, I get the default theme with some broken links to icons.
What am I missing? I'm sure it's simple but I can't manage to find out.