can't use POST with 1.0.1 + fastcgi

[gpg <giorgenes@gmail.com>]

Hello,

Sorry to bother you guys, I've been looking for this problem on the
web but can't figure out what it is.

I'm trying to use ruby 1.9.1 + rack 1.0.1 + fastcgi + lighttpd.
Everything works fine EXCEPT posts:

/!\ FAILSAFE /!\  2010-03-05 17:27:03 -0300
  Status: 500 Internal Server Error
  closed stream
    /var/lib/gems/1.9.1/gems/rack-1.0.1/lib/rack/rewindable_input.rb:
86:in `make_rewindable'
    /var/lib/gems/1.9.1/gems/rack-1.0.1/lib/rack/rewindable_input.rb:
26:in `read'
    /var/lib/gems/1.9.1/gems/rack-1.0.1/lib/rack/request.rb:134:in
`POST'
    /var/lib/gems/1.9.1/gems/rack-1.0.1/lib/rack/methodoverride.rb:
15:in `call'
    /var/lib/gems/1.9.1/gems/actionpack-2.3.4/lib/action_controller/
params_parser.rb:15:in `call'
    /var/lib/gems/1.9.1/gems/actionpack-2.3.4/lib/action_controller/
session/cookie_store.rb:93:in `call'
    /var/lib/gems/1.9.1/gems/actionpack-2.3.4/lib/action_controller/
failsafe.rb:26:in `call'
    /var/lib/gems/1.9.1/gems/actionpack-2.3.4/lib/action_controller/
dispatcher.rb:106:in `call'
    /var/lib/gems/1.9.1/gems/rack-1.0.1/lib/rack/content_length.rb:
13:in `call'
    /var/lib/gems/1.9.1/gems/rack-1.0.1/lib/rack/handler/fastcgi.rb:
58:in `serve'
    /var/lib/gems/1.9.1/gems/rails-2.3.4/lib/fcgi_handler.rb:103:in
`block in process_request'
    /var/lib/gems/1.9.1/gems/rails-2.3.4/lib/fcgi_handler.rb:153:in
`with_signal_handler'
    /var/lib/gems/1.9.1/gems/rails-2.3.4/lib/fcgi_handler.rb:101:in
`process_request'
    /var/lib/gems/1.9.1/gems/rails-2.3.4/lib/fcgi_handler.rb:78:in
`block (2 levels) in process_each_request'
    /var/lib/gems/1.9.1/gems/rails-2.3.4/lib/fcgi_handler.rb:77:in
`each'
    /var/lib/gems/1.9.1/gems/rails-2.3.4/lib/fcgi_handler.rb:77:in
`block in process_each_request'
    /var/lib/gems/1.9.1/gems/rails-2.3.4/lib/fcgi_handler.rb:76:in
`catch'
    /var/lib/gems/1.9.1/gems/rails-2.3.4/lib/fcgi_handler.rb:76:in
`process_each_request'
    /var/lib/gems/1.9.1/gems/rails-2.3.4/lib/fcgi_handler.rb:51:in
`process!'
    /var/lib/gems/1.9.1/gems/rails-2.3.4/lib/fcgi_handler.rb:23:in
`process!'

I've tried the patches in this link with no success:
http://www.litespeedtech.com/support/forum/showthread.php?t=3453

Could someone point me a solution?

Thanks in advance.