delphi - Error when running program with VirtualShellTools from a service -

i create service in delphi. need service run program. in windows 7, use code execute program :

procedure executeprocessasloggedonuser(filename: string);  implementation  function getshellprocessname: string; var   reg: tregistry; begin   reg := tregistry.create(key_read);   try     reg.rootkey := hkey_local_machine;     reg.openkeyreadonly       ('software\microsoft\windows nt\currentversion\winlogon');     result := reg.readstring('shell');       reg.free;   end; end;  function getshellprocesspid(const name: string): longword; var   snapshot: thandle;   process: tprocessentry32;   b: boolean; begin   result := 0;   snapshot := createtoolhelp32snapshot(th32cs_snapprocess, 0);   if snapshot <> invalid_handle_value     try       fillchar(process, sizeof(process), 0);       process.dwsize := sizeof(process);       b := process32first(snapshot, process);       while b       begin         if comparetext(process.szexefile, name) = 0         begin           result := process.th32processid;           break;         end;         b := process32next(snapshot, process);       end;           closehandle(snapshot);     end; end;  function getshellhandle: thandle; var   pid: longword; begin   pid := getshellprocesspid(getshellprocessname);   result := openprocess(process_all_access, false, pid); end;  procedure executeprocessasloggedonuser(filename: string); var   ph: thandle;   htoken, ntoken: thandle;   procinfo: tprocessinformation;   startinfo: tstartupinfo; begin   ph := getshellhandle;   if ph > 0   begin     if openprocesstoken(ph, token_duplicate or token_query, htoken)     begin       if duplicatetokenex(htoken, token_assign_primary or token_duplicate or         token_query, nil, securityimpersonation, tokenprimary, ntoken)       begin         if impersonateloggedonuser(ntoken)         begin           // initialize startupinfo structure           fillchar(startinfo, sizeof(tstartupinfo), 0);           startinfo.cb := sizeof(tstartupinfo);           // specify process runs in interactive desktop           startinfo.lpdesktop := pchar('winsta0\default');            // launch process in client's logon session           createprocessasuser(ntoken, nil, pchar(filename), nil, nil, false,             create_new_console or normal_priority_class, nil, nil, startinfo,             procinfo);            // end impersonation of client           reverttoself();         end;         closehandle(ntoken);       end;       closehandle(htoken);     end;   end; end; 

the code works fine "empty" program. drop tvirtualexpolorertreeview onto form of program. if start service there error when program being called. guess program can't enumerate pidl or blabla (i don't know windows shell). how force program can run normally?

your winsta0 might cause:

starting windows vista, way services (and processes started services) can interact desktop changed, services no longer run in same session user @ console.

by default, cannot interact desktop more.

see this thread nice links on matter.