fxping problems with router

[kenx]

heya
i just got myself a SOHO 10/100mbit DSL/Broadband hardware router a few days ago and everything works fine, except fxp transfers

i tried various sites from which i know that they support fxp transfers, and i also tried fxping using wingates and proxies nothing works, i only get an error saying:
425 Can't open data connection

any help on this issue would be greatly appreciated
thx in advance

greets
kenx