upload slows to zero with new firewall router

[roberto]

my basics:

* FlashFXP v[ 3].[0.2.], build [1045], [x ]registered, [ ]unregistered, [ ]pirated
* OS [ ] WinXP, [x] Win2K, [ ] Win98, [ ] WinME, [ ] Other
* Running behind NAT/router [x] Yes & Model [Netgear ], [DG834] No, [ ] Not sure
* Running firewall [ ] Yes, Name [ ], Ver. [ ], or [ ] No
* Running Antivirus [x] Yes, Name [Norton ] or [ ] No
* Network [x] xDSL, [ ] CABLE, [ ] Dail-Up, [ ] Other

since installing the new router, every upload slows down and somtimes stopps uploading in the middle of a file or reaching 100% of filesize but not finishing it.

can anyone please help?
Robert