Fix error handling in server-side POST.
Fix error handling in server-side POST.

darcs-hash:20060829183457-4cc09-afcc4c427d5e14224cb9daa0a30a5917ec4ffc76.gz

jeromelebel/polipo,fqtools/polipo,galeksandrp/polipo,clowwindy/polipo,jech/polipo,feijilei/polipo,feijilei/polipo,nxtreaming/chumen,galeksandrp/polipo,lkraider/polipo,fqtools/polipo,jech/polipo,Psiphon-Inc/polipo,ssb22/polipo2,toke/polipo,lkraider/polipo,fukusaka/polipo,feijilei/polipo,dxq-git/polipo,berkley4/polipo,caeies/polipo-caeies,gorakhargosh/polipo,galeksandrp/polipo,ajmgh/polipo,doublec/namecoin-polipo,lkraider/polipo,jech/polipo,akkakks/polipo,TierraDelFuego/opilop,Android-Apps/polipo,berkley4/polipo,nxtreaming/chumen,dxq-git/polipo,dxq-git/polipo,fqtools/polipo,Android-Apps/polipo,berkley4/polipo,danchr/polipo,akkakks/polipo,akkakks/polipo,strongwillow/polipo,ssb22/polipo2,nxtreaming/chumen,strongwillow/polipo,ssb22/polipo2