[neoxed]

I could never get it work either, so I wrote my own virtual->real path resolver.

proc ::nxTools::Pre::ResolvePath {UserName GroupName RealPath} {
    set BestMatch 0
    set ResolvePath "/"; set VfsFile ""
    set RealPath [string map {\\ /} $RealPath]

    ## Find the user vfs-file
    if {[userfile open $UserName] == 0} {
        set UserFile [userfile bin2ascii]
        foreach UserLine [split $UserFile "\r\n"] {
            set LineType [string tolower [lindex $UserLine 0]]
            if {[string equal "vfsfile" $LineType]} {
                set VfsFile [ArgRange $UserLine 1 end]; break
            }
        }
    }
    ## Use the group vfs-file, if the user vfs-file doesn't exist.
    if {![file isfile $VfsFile] && [groupfile open $GroupName] == 0} {
        set GroupFile [groupfile bin2ascii]
        foreach GroupLine [split $GroupFile "\r\n"] {
            set LineType [string tolower [lindex $GroupLine 0]]
            if {[string equal "vfsfile" $LineType]} {
                set VfsFile [ArgRange $GroupLine 1 end]; break
            }
        }
    }
    ## Use the default vfs-file, if the user or group vfs-file don't exist.
    if {![file isfile $VfsFile]} {
        set VfsFile [config read "Locations" "Default_Vfs"]
    }
    if {![catch {set Handle [open $VfsFile r]} ErrorMsg]} {
        while {![eof $Handle]} {
            if {[set FileLine [string trim [gets $Handle]]] == ""} {continue}
            foreach {VfsRealPath VfsVirtualPath} [string map {\\ /} $FileLine] {break}
            if {[string first [string tolower $VfsRealPath] [string tolower $RealPath]] == 0} {
                ## Use the longest available mount path (most accurate)
                if {[set Length [string length $VfsRealPath]] > $BestMatch} {
                    set ResolvePath [string range $RealPath [set BestMatch $Length] end]
                    set ResolvePath [file join $VfsVirtualPath [string trimleft $ResolvePath "/"]]
                }
            }
        }
        close $Handle
    } else {
        ErrorLog PreResolvePath $ErrorMsg
        ErrorReturn "Unable to resolve virtual path, contact a siteop."
    }
    return $ResolvePath
}

Feel free to use it, though you might have to change a few things for it to work with your script(s).