425 Data Conection:illegal seek

[data]

After I'm installing a Firewall I've got Problems with fxp.
125 Data connection already open; Transfer starting.
426 Connection closed; transfer aborted.
Transfer Failed!
TYPE A
426 Data connection: Illegal seek

some datasizes works -2 mb all sizes over i see the error-plz help Thx

[MxxCon]

well, according to you, it's a problem with your firewall.
check all rules that you are not blocking what you are not supposed to.