News from the Z:

Sony blocked the ability to rename/delete/move 'EBOOT.PBP' files inside of the PSPemulator. This wasnt a problem, thats why we have FBOOT (or VBOOT).
But sony introduced with Firmware 2.10 a new 'security patch', which prevents you from renaming or creating folders inside of the /PSP/GAME/ directory.

Ive found a way to bypass this 'security feature', so its again possible to create folders inside of /GAME/ (after the simple renaming trick).

By the way, creating/copying/deleting/renaming files inside of /GAME/ and inside of folders, inside of /GAME/, is indeed possible. Emulators and homebrews should work like usual, if you boot them via /GAME/ at FW 2.10!