VPN with iptables/poptop works. can reach lan but not server

i've setup a linux-vpn with poptop (pptpd) and connections etc
works fine. people can connect and play games with each other.
file shares can be reached between all the clients and even http
servers on several computers can be reached with their local ip's.

but the only problem is reaching the vpn-server itself. i can connect
to the pop3 server and list email. connect to ssh with the local ip
etc. get a samba-file listing. but when trying to connect to a share
it times out. the same for the apache server. the request get's to
the server and the server sends back some data. the first package
always arrives. a 'move permanent' arrives and the client redirects
to an other server for example. but normal pages always time out.
the request for the page get's to the server. the server sends back
the data over the vpn-tunnel and the first few packages arrives
and the rest times out so nothing is displayed. it looks like sequential
packages don't arrive. (a telnet 'server_ip' 80 does work (giving me
the right 'move permanent' for example). requesting something large
(my homedir) will show up nothing

what could this be?

my firewall settings:


Chain INPUT (policy DROP 65203 packets, 11M bytes)
pkts bytes target prot opt in out source
destination
1248 110K ACCEPT all -- ppp2 any 192.168.0.0/24
192.168.0.0/24
2031 362K ACCEPT all -- ppp1 any 192.168.0.0/24
192.168.0.0/24

Chain FORWARD (policy DROP 127 packets, 6096 bytes)
pkts bytes target prot opt in out source
destination
169K 98M ACCEPT all -- any any 192.168.0.0/24
192.168.0.0/24

Chain OUTPUT (policy ACCEPT 220M packets, 41G bytes)
pkts bytes target prot opt in out source
destination
14M 16G INT_OUT all -- any eth0 anywhere anywhere
44M 19G PUB_OUT all -- any ppp+ anywhere anywhere

so output shouldn't hold up anything...

hope some-one can help me out with this one.

kind regards,
Evert