LAN issue in only one of my Android devices

[Sincrono]

Hi,
Hi all....
I'm very frustrated with my google tv Tronsmart MK908. I have not done any modification to the OS, kernel, or anything like that. It has Android 4.2.2


In order to play movies located on an external HD (which doesn't work with the google tv stick), I connected it to a notebook running WIN7, and from there, I'm sharing certain folders through the wifi network (with WPA2 security, IPv4 network). I made all the configurations in order to support all permissions and no passwords. 2 of my Android devices (a smartphone and a Tablet running older OS's) do connect to the shared folder, without asking Username and password. A macbook does the same. However, with the Tronsmart MK908, when I try to enter the network server (through the same software used in the other android devices, I mean latest BsPlayer FREE 1.14 build 167), it asks for a username and password, and fails always (even if I write the correct password, though it shouldn't ask for it. The error is "Login Failure: Unknown Username or bad password). I repeat, the Android devices and the macbook never ask for password and enter the shared folders with no problem at all. I'm using the newest version of BSPlayer Free on the 3 Android devices. Strangely enough, I can connect to one specific shared folder located in the same notebook internal HD (it's a public folder), but i don't want to move everything to that location in order to get this working. However, this is done via eHomeMedia player (which I think came pre-installed), but this is an awful app that can enter to the WIN7 server but only to some of the shared folders (not the ones in the external HD).

I'm very confused, and don't know if a custom ROM (whose meaning I don't know) would solve this problem. I thought the mini pc would work out of the box, without hackings and strange (for me) modifications. I'm good with computation but at the software, not hardware level, so now I don't know if this is a software or hardware issue.

Any suggestions?
I have tried to change the display name (which shouldn't be related since as it name says it is only a display) of the lan network but I still can't enter.

Thanks a lot, any help will be appreciated.