MySQL query: search multiple strings in a single field, from CSV in other field/table?

I have a table that contains two TEXT fields with textual content, and in a separate table, a field that contains comma separate values of keywords that can be more than one word. The following query works in my WAMP using Appserv, does not works in our Hostgator LAMP...why??

SELECT 
    t.content_me, t.content_visitor, t.Id, exp.owner_user_id, exp.name
FROM (SELECT t.content_me, t.content_visitor
      FROM `texts` AS t 
      WHERE t.owner_user_id=1 *<== obviously this changes...*
      ORDER BY t.Id DESC) AS t 
INNER JOIN exp ON t.Id = exp.owner_user_id AND 
      t.content_me REGEXP (REPLACE(exp.keywords,',','|')) 
WHERE t.owner_user_id=e.owner_user_id=6 
ORDER BY t.Id DESC

Furthermore, if I literally put a value in this part:

t.content_me REGEXP (REPLACE(exp.keywords,',','|')) 

as lets say:

t.content_me REGEXP ('yeah|ok')

It works in Hostgator. So I guess the problem is that REGEXP (REPLACE(exp.keywords,',','|')) thingy...right?