I have just tried with last filezilla version and with vu+cc as well. I stopped antivirus too but same result..Are you using the VU+ Control Centre, or have you downloaded the latest version of Filezilla?
I have only read of this with Dreamboxes, from a number of years ago, and that mentioned firewalls, but as you've disabled Windows firewall you could check your anti virus software.
Never had this problem or even read of it, with VU+ receivers.
Do you have a laptop, running a different set up, that you can try?
update: I try with BH 2.1.7 same problem, this morning with LAN connection I have do online update to version 2.1.7 .1 and now works with wifi too!!!I tried without wifi (vu solo2 with LAN) and it works!!!
This is really strange...I try to reinstall wifi driver