Where did you create the WireShark log? Somewhere on the FTP server machine, near Rebex client, or somewhere along the way to Rebex client?
Please try to create two more logs - one wireshark log at the machine where the FTP client is running and another Rebex created log with LogLevel.Verbose. If you compare these two logs, do they correspond to each other?
If not, please send us both the logs to email@example.com for analysis.
P.S. Please note that when LogLevel.Verbose is used, the log also contains sensitive data, e.g. username and password. Before sharing it with us, make sure that you delete or ** * them from the log.