[Serusers] Registration failes

I have installed SER 0.8.11 on Mandrake 9.1 with its native MySQL and php and made MySQL-database with ser_mysql. The SER itself works fine with Messenger 4.7. Then I installed serweb and made all changes to its config.php and other files. Again it works ok but when I try to register a new user and answer to the e-mail that I get then there comes the following message: 400 Table 'aliases' not found in memory, use save("aliases") or lookup("aliases") in the configuration script first. We regret but your iptel.org confirmation attempt failed. Please contact info(a)iptel.org for further assistance. Back to login form. My registration details can yet be found in ser database from tables subscriber and pending at the same time. What goes wrong and what does that error message mean?