I cast my line, waited for 3 minutes, caught something, clicked to reel it in, and  got this message:

An unknown error occurred.

has_bite

I did also get the animation and the message that I was reeling in the fish, but it just went on for about 5 minutes before I gave up on it.

I don't know if fishing is going to work on your psp glorgoth.
If it works sometimes, that's lucky enough

Also, if it lasts more than 30 seconds, you've probably got a problem, so don't wait 5 minutes next time

I wasn't on a PSP at the time, and I only waited that long so I could let you know how long it was taking

You'll get an error if you open more than one fishing tab.

browser had tabs disabled

Very odd. I have no idea