Hm... That seems to be a problem. As I've written some time ago, fop needs for phpdoc almost 700MB memory (java -Xmx700000000 ... works currently. Note: with fop 0.20.5rc3, earlier versions need more).
That's why I've mailed James to put us on one of the machines with 1GB RAM while he was "moving around things", but I didn't get a feedback on this (I hope he did it).
Before my RAM-upgrade, I simply enlarged the swapfile on Windodws (But this wasn't good to work, it swapped around the whole night, while it now takes just 3-4 minutes).
But even I'm no expert on Linux, I think you don't have no other choice than to a) upgrade RAM, or b) enlarge your swap-partition. (Fact is, that your phys.RAM + swap-space must be at least 700MB (the 700000000bytes + all the running processes ...).
Hm. I think I would have enough swap. But it does not seem to attempt to use swap at all... Anyway, I'll try to contact the FOP team, and some linux support guys here ;) BTW I am not going to invest in any more SDRAM modules. Ron offered me a huge help in funding, I am awaiting that now. :) :(
Btw, i've just made an actual one for dl at http://www.t0.or.at/~sunny/php/php_manual_en_3.pdf.zip
This looks very decent! Great work! Why this is not ready for php.net publishing? It would be very wormly welcomed, I am sure. Even if we only have an English PDF. Guys are waiting to this for years... It has working links, nearly perfect formatting...
Goba