Yale Huang has released a Fixed version of the PDF player for the PSP, heres what he says on his site:
"I installed PSPPDF v0.2 to my PSP days ago. It's great expect the bug of color: it shows everything in red.
It's a small bug about color format, so I fixed it soon. (I failed to contact the original developer of v0.1 and v0.2.) Now, it's released as v0.2u1. There're still some know bugs. For example, it hangs when loading some large PDFs. I'll work on them later."