Problem with my ftp server (pure-ftpd)

[Sorry27]

Hello,

I have installed a ftp server (pure-ftpd) and is all ok, but there is a
little problem when I upload the files much large .
When I try to upload files much large, at the end of operation I can't more
give commands to ftp server, like if the connection were in stall !!! But
the files are correctly uploaded!

I have tried with ftp client installed with my RedHat 9.0 and with ws_ftp
client (Windows).
With ws_ftp I receive the following error:
-blocking call cancelled

I have tried with passive transfer, but the result is the same.

Anyone can help me?

Thanks in advanced.

Mulan