[SOLVED] Installation error with mysql

Hi there.
Tried it on 2 different machines: Linux Mint and Centos 6.5.
Unzipped projeqtorV5.1.5.zip in /var/www/html as root.
Do I have to change permissions or ownership of projeqtor or its some specific subdirectories?
Are there some installation instructions that I am missing?
Do I have to edit some config file with some mysql user name and password?
Because this is the error I am getting in red and it is not going away. I cannot proceed further at all:

SQLSTATE[HY000] [1045] Access denied for user 'root'@'localhost' (using password: YES)
dsn = mysql:host=127.0.0.1;port=3306

If I type mysql -u root -p at shell prompt, I am able to log into mysql with root's password.
I am stuck there. Please help.
Thanks in advance.

Many thanks for your reply babynus.
root is the mysql user.
If I type mysql -u root -p at shell prompt, it asks for password.
If I enter the root's password correctly, it logs into mysql.
I tried leaving the db password column empty. It says this in red: incorrect value for 'Default password for initialization', field is mandatory.
If the default password is hard-coded in some config file, please tell me so that I can amend it.
Let me tell you another thing: None of the files are created or amended so far by the installation process. I had tried chown -R 777 projeqtor . It does not create or modify any file.
There is no parameter file in tool directory.
I did not change the following values in the set up screen:
../files/attach/
../files/report/
../files/logs/projeqtor_${date}.log
../files/config/parameters.php
Do I have to remove dots? Give full path names?
I do not see any logs created anywhere.
What am I doing wrong?

Figured it out.
Here are my steps to get it to work on Centos 6.5:
1. Unzip into /var/www/html . You need to be root.
2. chmod 777 tool
3. change the default mysql root password to your mysql root password in here: tool/config.php
4. Visit this with your browser: localhost/projeqtor
5. You will see the list of module. Install any modules that are shown missing.
6. Create a directory such as projeqtor somewhere outside the web root. chown apache.apache to that directory.
7. Change the following defaults to this new directory. I used full path names.
../files/attach/
../files/report/
../files/logs/projeqtor_${date}.log
../files/config/parameters.php
8. Changed other params such as time zone, currency, mail ids etc.
Then it worked.
Changed permissions back to normal on tool.
Hope it helps someone.
Question: Is it safe to chown -R apache projeqtor right after unzipping the package in web root?