PCLinuxOS-LiveUSB Creator ......... you should have a livecd.sqfs file and an ISOLINUX directory with some 50+ files in it.
I suggest redoing the remaster, this time using the option 'workdir' and maybe the 'gz' compression option (for speed and as a USB is being used there is no need to reduce size for a CD).
If it fails to create an ISO, the files it would have used remain in the workdir for use by LiveUSB Creator.
I have remastered very large systems in this way .... up to 15GB sqfs file! .... and run them from a 16GB USB stick.