My b2evolution Version: Not Entered

hey guys, when I go to User's tap and try to alter my password, there is no Save button. Instead it says, "Fatal error: Allowed memory size of 8388608 bytes exhausted (tried to allocate 19456 bytes) in /opt/lampp/htdocs/blog/plugins/_auto_p.plugin.php on line 157" what can that mean?

Thanks a lot in advance.