Cannot connect to database in store after upgrade

I upgraded to Zencart 1.3.8a, which then wanted to upgrade my database, after which I get the following message on my website (store):

Sorry!
There seems to be a problem connecting to our database. Please give us a few minutes to remedy the problem. Thank you.

I can log into my admin pages fine and can see my database records, but just can't connect in my website store. Both my configure.php files are the same. I have played around with a few changes but none have worked. I have created another user and password and tried to use that but it never worked either. My brainstorming is not storming anymore. I'd appreciate any help.

jcattanach:

Both my configure.php files are the same.Identical?
They shouldn't be.

No, sorry, I meant that they were the same with regards to the database name, username, password info (in define our database connection)

What permission level is set on your /includes/configure.php file?

Permission level is 644

jcattanach:

Sorry!
There seems to be a problem connecting to our database. Please give us a few minutes to remedy the problem. Thank you.This message only appears when Zen Cart cannot connect to your database successfully.

How it works:
a) the configure.php file is read, loading the database settings
b) a connection to the database is attempted
c) if a failure happens here, you'll get that message
d) if connection is successful, it attempts to access the specified database-name
e) if a failure happens here, you'll get that error message
f) if connection is successful, normal store operation proceeds.

So, if the configure.php file is incomplete, not readable by PHP, or has PHP syntax errors in it, you'll have a problem.
If the database settings cannot be used to successfully connect to the database and access the group of tables used for Zen Cart, you'll have a problem.