speed problem

I bought smartFTP on 19th september 2006, so I think I need your help.
When I upload some files the speed maximum connection is about of 350/400 KB/s.
This is very strange 'cause when I tried to upload the same files with Ftp explorer my speed upload is about 1000 KB/s. I have a broadband.
I tried to upload my smart ftp version to v.2.5.1005 but nothing changes.
What I have to do?
Please help me.

One more information:
Upgrading to new version I lost my italian client localization. Why?

Hello ..

I have answered your questions in an email.