Apache .htaccess <ifModule not allowed here
You need to configure your apache to enable configuration from the .htaccess file. So in the directory section be sure you have the option
Allowoverride ALL
for more information more information about allowoverride.
In your setup if you use only mod_rewrite maybe you can set only FileInfo , I always set the Options parameter to SymLinksIfOwnerMatch to be able to perform redirection to other sites.
Allowoverride FileInfo
Options SymLinksIfOwnerMatch
I hope it will help, if you already set this configuration please add information with your virtualhost configuration.