occasional ftp upload failure

[espi]

I am evaluating APBackup v2.7.2050 for ftp uploading. But I recieve following error occasionally during uploading, and the tranfer stops.

FTP: "myip" ['RT *,*,*,*,*,* ':command not understood]


Is this a problem in my ftp server or in this program? I think somehow first two letters in PORT commands are cut-off. I can't use passive mode. Any other suggesting will be appreciated.

ESPI