Not able to upload a darn thing

Ok...a week ago I install a new Linksys WRT54GX and now I have excellent signal stregth all over my house and the yard. A few days after I installed it I started having trouble uploading files to my web site on Verizon...they would hang and timeout. To get around the problem I would use verizon's propriatary web building software and upload some stuff w/it and that would usually be enough and my ftp client would connect and all would work.

Two days ago that trick stopped working. I can d/l from webbie...I can delete off it...I just cannot upload to it. So I called Verizon and they gave me the song-n-dance and were able to upload from their location to my webbie perfectly fine. On a lark I tried upload to another site (not verizon) and darn if that didn't fail as well. It seems to allow the first few bytes then hangs to a server timeout condition.

I tried resetting my MTU to a lower figure...no go, I reset my router...no go...I tried another PC on the network...no go...I reset my modem..no go, a friend setup another ftp site on another port (not 21) and it failed. I tried everything I know and bumpkis.  I then went back to my old router and all was fine.