General Domain, Hosting & MYSQL query

Hi I am new to this to please bear in mind.

Can anyone please advise if my current approach is a correct one
I have bought a few domians and currently host these on the same host (web-mania) which allows me one MYSQL database
Note I have seperate folders on the host for each domain and my domains are set up to point to each folder — Is this recommended?

I set up 1 domain which uses the MYSQL and all worked well

With my second domain I wish to also use the same database (different tables tho), however when I attempt to login (using the same login script as th successful one (but the login scripts are in a different folder) I get
Forbidden You don’t have permission to access X file
Note this file is a loginck.php file

I have checked all the UNIX permissions and all appear OK.
Someone has mentioned it may be due to DNS ?

Can I have different domians which point to the same webhost (different folder) all set up with the same DNS settings ? or will this clash

any advise appreciated

I have since found ( I wasn’t going mad)
When you set up several domains against the same web-mania hosted area (different folders) then after creating a sub domain you also then need to instruct web-mania to change their settings to allow the domain to work (pointing to a different folder)
This will then allow the new domain to share a MYSQL database

I didn’t expect this manual web-mania intervention ?