Why do i get mysql error on same tables different names?

[lonerunner]

I have 2 almost exactly same tables, when i want to pull data form one i get error and for another it works. I really don't know what can be the problem

 

This is joomla cms and one table is called jos_users and another table is called jos_va_affiliates, they both have same fields (id, name, username, email, password, country, etc...) I want to pull just 4 fields, id, name, username, email. When i try to pull from jos_va_affiliates table it works, but when i try from jos_users i get this error "mysql_num_rows() expects parameter 1 to be resource, boolean given"

 

Query goes like this

 

 

        $query = 'SELECT aff.id AS id, aff.name AS name, aff.username AS username, aff.email AS email'
            . ' FROM #__va_affiliates AS aff'
 

 

 

And this works, the only thing that is different is table so when i try

 

 

 

        $query = 'SELECT aff.id AS id, aff.name AS name, aff.username AS username, aff.email AS email'
            . ' FROM #__users AS aff'
 

 

 

I get error i mentioned above.