Have you installed the 5.00 m33 1.50 kernel add-on?? if not, you can download it
HERE
And you can get the 1.50 eboot
HERE
All the instructions is in the readme file in the 1.50_addon500.rar file
Once you have installed the 1.50 addon, turn off your psp, then turn it back on HOLDING the R-TRIGGER. This will make your psp go into recovery mode. Once you are in recovery mode, select Configuration -> Then Game Folder Homebrew. Select this until it says 1.50 kernel.
PS. Is this a PHAT psp or SLIM????