Problem running Sangoku Rensenki otome no heihou for PSP

[cinnamonroll]

Hi, I'd like to know if someone could help me, I'm trying to play Sangoku Rensenki Otome no Heihou ( [120726][PROTOTYPE] 三国恋戦記 ～オトメの兵法！～ ) at psp but when I run the disc 1 the main window with the title and characters stay just grey without any options, so I can't even try to install the disc.
I have a psp 1000 and the software is 5.50 Prometheus

thanks in advance