OK, so you are running active FTP, no firewalls, your macros always get the connection and successfully do CWD. In that case, apart from looking at the FTP server's log (a good suggestion I sadly didn't think of), you may also setup a packet sniffer and filter all traffic between server's ports 20-21 and client's IP address. Find a failing session and a working one by timestamp. Compare the results. Look for the order of the packets before the first data block is sent. Check that the ACK's are in proper place, etc. This is a bit laborious, so start with the server log. Packet trace may come handy if you open a PMR.
Ivica Brodaric
