Your not using an 8gb memory stick are you?
I'm not sure about doom. I used to play a version that worked fine, the version you linked to says it runs under the 3.x kernel. I'm running 1.5 so you'd have to ask someone else about that one.
The current Duke3d PSP port is very buggy, It crashes for me on loading the 2nd level, and for many others (it was discussed in the release thread).
Quake: You meant you copied the 'ID1' folder yeah? There is no 'dn1' folder in a default install of quake 1. Those errors don't come up for me (those commands are not listed in my config.cfg file). Try deleting the config.cfg file from your ID1 directory (quake should rebuild a default config file). I'm using HW_KM not HW_UM, I don't know if running the kernel mode version would work any differently.
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