gopm在win8.1上无法正常工作

On Windows(win8.1), $GOROOT=D:\go, $GOPATH=D:\projects\go\goprac,<br> I have a project(demo from [gopm][1]) in the directory(G:\\), and when I run command "gopm build", there comes out an error

g:\Demo>gopm build<br>
[GOPM] [36m14-12-20 12:49:26[0m [[35mFATAL[0m] fail to list imports:<br>
 fail to get imports(Demo): cannot find package "Demo" in any of:<br>
        D:\go\src\Demo (from $GOROOT)<br>
        g:\Demo\.vendor\src\Demo (from $GOPATH)<br>
        D:\project\go\goprac\src\Demo

But, the same code on win7 runs successfully. On both side, I install gopm through the command "go get -u github.com/gpmgo/gopm", and Add "gopm.exe" path into $PATH variable

Anyone knows something about this problem?