FTP upload failing when filtering on

[SuperFly_za]

Hello

I have a strange problem with a newly install PFS box, if I enable filtering then FTP uploads start but +- 250Kb of the upload the upload stops, it is almost like the connection dies. If I turn filtering off then uploads complete correctly.

This is my setup:

Lan –> PFS Box --> Radware linkproof --> ADSL Routers --> Internet

I have also tried creating a rule on the firewall on both sides with allow all and any and the problem persists.
I've considered skipping the radware unit from doing the balancing of ADSL Lines but it does a brilliant job at that so would prefer to avoid that scenario.

Any help would be appreciated.