hi all, im not sure if i got this in the right place on this forum but i hope one could help

I'm new to this vpn stuff but i have picked up a lot on this lately, i do how ever have a problem with file transfer speeds via vpn

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i have set up vpn on my vista ultimate pc, i have put the ports in the windows firewall, and set up a static ip and port forwarding on my sweex's router, also set up DDNS on my router as my internet provider changes the ip once a week or so, Makes it easier to connect than trying to get my public ip every time i need to do vpn

the client end is my iphone 3g, that does connect fine,

if i go to the BBC iplayer on my iphone via my vpn that works, (only way i could think of to get BBC iplayer to work over 3g as it is normally restricted).... i can do what ever i like on the internet via vpn and no problems with speed there.

but when using a program on my iphone (netportal), to access my shared files, they will only download to my iphone at 15 Kilobytes per sec

i have also connected to a FTP server from my iphone via vpn and get about 90 Kilobytes per sec down... which is about right for my internet speed.

I'm on Virgin media 20mb
2486 Kilobytes down
92.5 Kilobytes up (not Kilobits)

does anyone have any idea whats going wrong with this....
i hope i have gave enough info, but if not, just ask

thank you all