Hi vrdriver, I was aware of those files.
They were set right.
The site had been running on the server but I updated it localy and then transferred the database from my machine to the server. After manually clearing the cache and trying to enter the manager, I got this error. I tried then the setup to make sure I was making the necessary changes, but couldn't pass the summary page with the error given above.
BobRay my first thought was that. but... if the credentials were wrong, How did it manage to connect when not in the setup page?
I asked my host to delete everything and then unpack a zip file of my entire site.
After they did so, I could enter the manager (previous update of all 4 config files) but was still greeted with this 'database connection failed' error.
Searching in the forums I found this:
https://github.com/modxcms/revolution/issues/9037#issuecomment-35756827
I disabled OPcache in /setup/index.php and setup passed ok.
But now entering the manager gives me this:

In the logs, I saw that the setup had had errors:
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not copy /home/fd000507/public_html/core/packages/core/modContext/1addb0eebb283494c91b2e4951f5e8f3/0/ to /home/fd000507/public_html/index.php
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not copy /home/fd000507/public_html/core/packages/core/modContext/1addb0eebb283494c91b2e4951f5e8f3/1/ to /home/fd000507/public_html/ht.access
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not copy /home/fd000507/public_html/core/packages/core/modContext/5ba74f82e6e4c998bcb120dd4e1729de/0/ to /home/fd000507/public_html/manager/assets
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not copy /home/fd000507/public_html/core/packages/core/modContext/5ba74f82e6e4c998bcb120dd4e1729de/1/ to /home/fd000507/public_html/manager/controllers
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not copy /home/fd000507/public_html/core/packages/core/modContext/5ba74f82e6e4c998bcb120dd4e1729de/2/ to /home/fd000507/public_html/manager/templates
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not copy /home/fd000507/public_html/core/packages/core/modContext/5ba74f82e6e4c998bcb120dd4e1729de/3/ to /home/fd000507/public_html/manager/min
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not copy /home/fd000507/public_html/core/packages/core/modContext/5ba74f82e6e4c998bcb120dd4e1729de/4/ to /home/fd000507/public_html/manager/ht.access
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not copy /home/fd000507/public_html/core/packages/core/modContext/5ba74f82e6e4c998bcb120dd4e1729de/5/ to /home/fd000507/public_html/manager/cache.manifest.php
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not copy /home/fd000507/public_html/core/packages/core/modContext/5ba74f82e6e4c998bcb120dd4e1729de/6/ to /home/fd000507/public_html/manager/index.php
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not install files from /home/fd000507/public_html/core/packages/core/xPDOFileVehicle/f69d2532b941b5c02baa0e91605c3cd5/ to /home/fd000507/public_html/connectors/
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not install files from /home/fd000507/public_html/core/packages/core/xPDOFileVehicle/a435b016ed96b4917ddc369091e616a6/ to /home/fd000507/public_html/connectors/
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not install files from /home/fd000507/public_html/core/packages/core/xPDOFileVehicle/9a9c76f3430b70ceadd9043bd8262df1/ to /home/fd000507/public_html/connectors/
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not install files from /home/fd000507/public_html/core/packages/core/xPDOFileVehicle/313363b666aa9bb23f88c4636950a70f/ to /home/fd000507/public_html/connectors/
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not install files from /home/fd000507/public_html/core/packages/core/xPDOFileVehicle/2194465f580face3d0b866ea2f0bac34/ to /home/fd000507/public_html/connectors/
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not install files from /home/fd000507/public_html/core/packages/core/xPDOFileVehicle/af74986f8155921677fd773a4fed8a73/ to /home/fd000507/public_html/connectors/
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not install files from /home/fd000507/public_html/core/packages/core/xPDOFileVehicle/cfb2f4d61a1ea4694b25022283d2214f/ to /home/fd000507/public_html/connectors/
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not install files from /home/fd000507/public_html/core/packages/core/xPDOFileVehicle/2e18d411d989764c5b48190712d67da2/ to /home/fd000507/public_html/connectors/
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not install files from /home/fd000507/public_html/core/packages/core/xPDOFileVehicle/98de724da88d4bcf3ed6eb3533a92e92/ to /home/fd000507/public_html/connectors/
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not install files from /home/fd000507/public_html/core/packages/core/xPDOFileVehicle/67a957988eef48baea7898466394db83/ to /home/fd000507/public_html/connectors/
[2014-04-26 18:53:54] (ERROR @ /setup/index.php) Could not install files from /home/fd000507/public_html/core/packages/core/xPDOFileVehicle/05e4be5b3da4a54c80a3bce40584a7b5/ to /home/fd000507/public_html/connectors/
Thanks for your input,
Abner