solved the "problem" with menu of "Tools"
nav.inc.php was encoded and brokes the menu of tools :-/
We just wrote a new file of "nav.inc.php" and now it shows the fault:
<<The encoded file /home/admispconfig/ispconfig/web/tools/tools/remote/userlist.php has expired.<<
Dont know, if everybody, who has installed this extension, just have a broken menu now.
We are no deleted the extension and the menu 'Tools' ist now ok.
Would be really better, to stop the dowload of the package from the website!