Mamp-xampp problem

[cool11]

I installed mampp to my macbook. I put the mysql database in db folder, I do the same with my php files in htdocs.
But I cannot see anything in my browser when I hit http://localhost/ http://localhost:8888/ for mamp.
Blank page!

No error message displayed.

Of course there are log files but it seems to be a stupid problem.
Is there any other mysql service running from mac os?
What do I have to do?


I tested xampp also and the results were the same.
I can now see a terminal window in my dock:
chown: /Applications/MAMP/logs/mysql_error_log: Operation not permitted
A mysqld process already exists

Is this the problem?
What do I have to do?

[cool11]

Here is an error message from xampp:

Warning: Unknown: failed to open stream: Permission denied in Unknown on line 0

Fatal error: Unknown: Failed opening required '/Applications/xampp/xamppfiles/htdocs/29/index.php' (include_path='.:/Applications/xampp/xamppfiles/lib/php') in Unknown on line 0

Here is another one, because it does not even open in browser its own page!
Warning: fopen(lang.tmp) [function.fopen]: failed to open stream: Permission denied in /Applications/xampp/xamppfiles/htdocs/xampp/lang.php on line 2

Where do I put my database in xampp?