I know where he's coming from - after 2 years of placing 1.5 kernel emulators in PSP/GAME150 it takes your mind to be re-trained to placing emulators in GAME folder 
To help clarify things, taken from the readme.
Open the V1.50 folder.
Open the PSP folder, Open the GAME folder.
Drag and Drop %__SCE__PSPUAE & __SCE__PSPUAE to the GAME folder of your
MS (normally ms0:PSP\GAME\), See below (typical dir structure).
MS0:(MemoryStick ROOT DIR)
|
|-PSP\
|
|-GAME\
It may prompt you to Overwrite, click "yes to all".
------------------------------------------------------------------------
V1.00 / Slim and Custom Firmware Install. <------------------------This is what should be done with custom firmware......
Open the V1.00_CFW_SLIM folder.
Open the PSP folder, Open the GAME folder.
Drag and Drop the PSPUAE folder to your MS (normally ms0:PSP\GAME\),
See below (typical dir structure).
MS0:(MemoryStick ROOT DIR)
|
|-PSP\
|
|-GAME\
It may prompt you to Overwrite, click "yes to all".
------------------------------------------------------------------------
With Custom Firmwares, you may also use the old V1.50 KXPLOITED EBOOT, <-----This is what should be done with custom firmware wanting to use the 1.50 Version......
Open the V1.50 folder.
Open the PSP folder, Open the GAME folder.
Drag and Drop %__SCE__PSPUAE and __SCE__PSPUAE to the GAME150 folder of your
MS (normally ms0:PSP\GAME150\), See below.
MS0:(MemoryStick ROOT DIR)
|
|-PSP\
|
|-GAME150\
It may prompt you to Overwrite, click "yes to all".Although V1.00 EBOOT is a FW V1.00 EBOOT, it is untested on PSP FW V1.00, but
it should work.