问个fsdbdump的问题

dump Systemverilog的design时
如何将所有的信息都dump出来
在testbench里应该怎么写$fsdbDumpvars
ug上说有一个“+all”参数可以全部dump
ug中说可以这样
$fsdbDumpvars ([level] [,[ ["+struct"|"+mda+packedOnly"|"+mda"|"+all"] |
"+class" ]] [, module | var]* );
但我像下面这么写的总是报错
  initial
    begin
      $fsdbDumpfile("sv_example.fsdb");
      $fsdbDumpvars(0,"+all",top);  
    end
Log如下：
Error-[ACC-ONF] ACC object not found
At time 0, in PLI routine called from ./fsdb.txt, 4
  In acc_handle_object call, object '+all' was not found in the design.
  Please ensure that the object exists in the design.
Error: Cannot find the instance(+all).
       From $fsdbDumpvars at time 0 in file ./fsdb.txt line 4:
Error: Syntax error :
        $fsdbDumpvars(level [,list_of_modules_or_variables]); or
        $fsdbDumpvars("+no_functions" | [ "+Reg_Only" | "+IO_Only"] |
                        "level=", level_var
[,list_of_modules_or_variables]);
是不是我的$fsdbDumpvars写的有问题
还我是少加了PLI？（我只加了下面两条）
-P /home/mengbo/novas/share/PLI/vcs/LINUX/novas.tab \
   /home/mengbo/novas/share/PLI/vcs/LINUX/pli.a \
求各位高人指点！

1. edit modelsim.ini,replace Veriuser = veriuser.sl to Veriuser = $\novas.dll  for example, c:\novas\debussy\share\pli\modelsim_pli\winnt\novas.dll .  semicolon must be deleted
2. set system variable PLIOBJS= C:\Novas\Debussy\share\PLI\modelsim_pli54\WINNT\novas.dll
3、 the following block in your testbench
initial  begin
$fsdbDumpfile(“filename_you_want.fsdb”);
$fsdbDumpvars;
end

you can generate fsdb file .
enjoy it

$fsdbDumpvars 0 {top};    
0 means all signal under this hierarchy