I clicked "Go>Network Drives".
I clicked on the server called "GREEN ROOM".
I waited a while, and then got an error message: "Failed to retrieve share list from server: Connection refused"
After stuffing around for a long time stopping and restarting my samba daemons and stuff like that, I noticed that PCManFM had the wrong thing in the address bar - it was smb://green%2520room/ (or possibly smb://green%25%20room/).
I changed the address to smb://green%20room/ and then all my shares were listed :)
I clicked back, and then clicked on "GREEN ROOM" again, and this time it got the address right...
So - is this a bug in pcmanfm, or is the problem with gvfs or something?