i had this same problem not to long ago, you should try using lspfix.exe and cleaning up your winsocks. This fixed my problem. This thread was discussed on the forum earlier, ioFTPD has "issues" with Mcaffee av and in my case Zero Knowledge firewall.
I was unable to replicate this (might be something I've fixed along with optimizations, already) I tried timeout by creating a download session from linux & then shutting down the device to prevent tcp error notifications.