Ran into this issue a couple of times already, duplicating it here so I dont' have to go dig for it again:
Error
[crit] (2)No such file or directory: mod_rewrite: could not init rewrite log lock in child
Fix
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_METHOD} ^TRACE
RewriteRule .* - [F]
</IfModule>
To this:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_METHOD} ^TRACE
RewriteRule .* - [F]
RewriteLog /var/log/apache2/rewrite.log
RewriteLogLevel 0
</IfModule>
Original reference is here