Simply password for your mysql user "root" is not correct.
Default proposed value is "mysql", but linux installs set no password : try without a password (set "db password" to empty value)
... but maybe you changed root password on mysql install 😉

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?

I tried leaving the db password column empty. It says this in red: incorrect value for 'Default password for initialization', field is mandatory.

You tried and set to null the default password for projeqtor, this is the default value to set password for new projeqtor users.
What you have to change is "Database password for user", and set it to your mysql "root" user.

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?

3. change the default mysql root password to your mysql root password in here: tool/config.php

This step is not usefull : you'll be able to change db password on the config screen.

Question: Is it safe to chown -R apache projeqtor right after unzipping the package in web root?

Yes, it is a good practice. With rights 755, all will work fine.
If you want to be even more secured you can set rights to 555 except for following folder (to keep 755) :
/files/* (and/or directories you configures)
/model/custom
/plugin/*
With this configuration, you'll be sure your folders are protected against unextected change.
You'll just have to adapt rights when deploying new version and possible when deploying some plugins.

Sorry.This post was an error. I can not delete it.