I understand. I use a 4gb Sandisk stick.
I tried using other games to confirm there wasn't an issue. All of the games I've tried will boot without popsloader, some of them just won't do much from then on (Vagrant Story hangs on the first load screen.)
I noticed 3 different options in PSAR depending on which key you pressed, could using the wrong option have dumped unusable prx files?
Yes, popsloader only works with decrypted modules. You have to press square.
If you try redumping the files again make sure to delete the F0 folder on your memory stick, since I don't think PSARDumper will overwrite the old files.