I'm having the same issue with the latest version (3.4 official), that I was having with the redsquirrel87 version v3.3.312 and up.
Which is: videos do not play from external drive, it just tells me that the ram or the cpu is too slow, it shows nothing but a black screen with no sound, then the PS3 crashes and I have to restart it.
The latest release which is working for me is still: v3.3.307 (Dec 06, 2011) from redsquirrel
If any anyone is encountering this same issue, and somehow find a way to fix it. Please let me know.