Error with network backup

I’m using Comodo Backup V. on Win XP Pro 32 bit SP3.
I’m trying to set a network computer as the destination. I see the list of my network computers, but when I try to browse one of them to choose a folder, I get the following error:
“Could not connect to network computer”.
If I cut and paste the whole path in the Save As combo box, all is ok. Also if I write the name of a share after the computer name, all the existing folders appear in the combo box. Still I’m not able to browse them visually.
Thanks, Francesca