Okay, i fixed it with this change.
find in /archive/index.php:
PHP Code:
{
print_no_permission();
}
replace it with:
PHP Code:
{
echo "<center><font face=verdana, arial, helvetica size=3>You are not allowed to view posts in $vboptions[bbtitle] until you will <a href=\"$vboptions[bburl]/register.php?\">register</a> as member.</font></center>\n<hr />\n";
print_no_permission();
}