Database error

Good evening,

This happens when I want to upgrade the memberlevel.

First there was this error with the memory level, but I solved this by doing this in my htaccess php_value memory_limit 48M atleast it doesnt show up again.

Now I recieve a database error it links me to this

Mysql error: Column 'DateStarts' cannot be null

Found error in the file '/var/www/vhosts/24-community.de/httpdocs/inc/membership_levels.inc.php' at line 163.
Called 'fromMemory' function with erroneous argument #2.

the line is this one here

Limit 0,1

I hope you guys can help me out here :)

I can´t even save the member profile without changing the membership level :(

But I remember that it worked bevor and I´m pretty sure I didnt touch this area