Check log file and report any error.

There it is.

It seems that the parameter table can't be found ...

2017-03-06 21:27:38.351 ** ERROR ** Exception-[42S02] SQLSTATE[42S02]: Base table or view not found: 1146 Table 'my_db_name.parameter' doesn't exist
2017-03-06 21:27:38.351 ** ERROR ** For query : select * from parameter where (idUser is null and idProject is null)
2017-03-06 21:27:38.352 ** ERROR ** Strack trace :
2017-03-06 21:27:38.352 ** ERROR ** #0 Sql->query called at [/home/db_user_name/public_html/projeqtor/model/persistence/SqlElement.php:1740]
2017-03-06 21:27:38.352 ** ERROR ** #1 SqlElement->getSqlElementsFromCriteria called at [/home/db_user_name/public_html/projeqtor/model/Parameter.php:665]
2017-03-06 21:27:38.352 ** ERROR ** #2 Parameter->getGlobalParameter called at [/home/db_user_name/public_html/projeqtor/view/login.php:274]
2017-03-06 21:27:38.352 ** ERROR ** #3 include called at [/home/db_user_name/public_html/projeqtor/tool/projeqtor.php:190]
2017-03-06 21:27:38.352 ** ERROR ** #4 require_once called at [/home/db_user_name/public_html/projeqtor/view/main.php:37]

What is content of your database ?
Do you have any table existing in this table ?

Sorry, I should have been more precise : this error log is coherent with what I have in my db.

The db name and the user name used by ProjeQtor are correct.
This user has all the available rights but the db is empty.

When I installed ProjeQtor I copied its folder to my server and filled the configuration form available on the default page.

I thought ProjeQtor would have created all the tables needed but obviously it didn't.

Did I miss something ?

which Server operating System is in use?

the Apache webservice Needs full Access rights to projeqtor and the subfolders.

All tables should be created at first connection of admin...

Please try again and post error logged in log file.
(from your previous example, error was logged at 13:01:22 and you show part of log at 21:27:38)

I obtain this error (it is repeated again and again in the log file) :

2017-03-10 11:25:11.188 ** ERROR ** Exception-[42S02] SQLSTATE[42S02]: Base table or view not found: 1146 Table 'u935180926_pjtr.parameter' doesn't exist
2017-03-10 11:25:11.237 ** ERROR ** For query : select * from parameter where (idUser is null and idProject is null)
2017-03-10 11:25:11.237 ** ERROR ** Strack trace :
2017-03-10 11:25:11.238 ** ERROR ** #0 Sql->query called at [/home/u935180926/public_html/projeqtor/model/persistence/SqlElement.php:1740]
2017-03-10 11:25:11.238 ** ERROR ** #1 SqlElement->getSqlElementsFromCriteria called at [/home/u935180926/public_html/projeqtor/model/Parameter.php:665]
2017-03-10 11:25:11.238 ** ERROR ** #2 Parameter->getGlobalParameter called at [/home/u935180926/public_html/projeqtor/model/UserMain.php:132]
2017-03-10 11:25:11.238 ** ERROR ** #3 UserMain->__construct called at [/home/u935180926/public_html/projeqtor/model/User.php:38]
2017-03-10 11:25:11.238 ** ERROR ** #4 User->__construct called at [/home/u935180926/public_html/projeqtor/tool/projeqtor.php:2611]
2017-03-10 11:25:11.238 ** ERROR ** #5 getSessionUser called at [/home/u935180926/public_html/projeqtor/tool/projeqtor.php:144]
2017-03-10 11:25:11.238 ** ERROR ** #6 require_once called at [/home/u935180926/public_html/projeqtor/view/main.php:37]

and the log file ends like so :

2017-03-10 11:25:32.767 ===== TRACE =====
2017-03-10 11:25:32.767 ===== TRACE ===== =====================================
2017-03-10 11:25:32.767 ===== TRACE =====
2017-03-10 11:25:32.767 ===== TRACE ===== DataBase actual Version =
2017-03-10 11:25:32.767 ===== TRACE ===== ProjeQtOr actual Version = V5.3.3
2017-03-10 11:25:32.767 ===== TRACE =====
2017-03-10 11:25:32.767 ** ERROR ** ERROR **
2017-03-10 11:25:32.767 ** ERROR ** on file '/home/u935180926/public_html/projeqtor/tool/projeqtor.php' at line (2555)
2017-03-10 11:25:32.768 ** ERROR ***** cause = set_time_limit() has been disabled for security reasons

This server runs on Linux (I don't know which build/version) : it's a free hosting service and pretty much everything is interfaced

I haven't found yet any means to configure Apache, (still searching) does it considers by default that it can't access a folder until I say so ?

Your provided disabled the command set_time_limit()

To try and have something working, try and disable this feature.
in /tool/projeqtor.php, replace function

function projeqtor_set_time_limit($timeout) {
  if (ini_get ( 'safe_mode' )) {
    traceLog ( "WARNING : try to extend time limit to $timeout seconds forbidden by safe_mode. This may lead to unsuccessfull operation." );
  } else if (! function_exists('set_time_limit')) {
  	traceLog ( "WARNING : try to extend time limit to $timeout seconds but set_time_limit has been disabled. This may lead to unsuccessfull operation." );
  } else {
    $max = ini_get ( 'max_execution_time' );
    if ($max != 0 && ($timeout > $max or $timeout == 0)) { // Don't bother if unlimited or request max
      @set_time_limit ( $timeout );
    } else {
      @set_time_limit ( $max ); // Set time limit to max to reset current execution time to zero
    }
  }
}

to

function projeqtor_set_time_limit($timeout) {
  return; // Disable this feature
  if (ini_get ( 'safe_mode' )) {
    traceLog ( "WARNING : try to extend time limit to $timeout seconds forbidden by safe_mode. This may lead to unsuccessfull operation." );
  } else if (! function_exists('set_time_limit')) {
  	traceLog ( "WARNING : try to extend time limit to $timeout seconds but set_time_limit has been disabled. This may lead to unsuccessfull operation." );
  } else {
    $max = ini_get ( 'max_execution_time' );
    if ($max != 0 && ($timeout > $max or $timeout == 0)) { // Don't bother if unlimited or request max
      @set_time_limit ( $timeout );
    } else {
      @set_time_limit ( $max ); // Set time limit to max to reset current execution time to zero
    }
  }
}

Maybe you'll be able to install PrijeQtOr.
But this may lead to non working features (export to PDF for big plannings, copy of big projects, ...)

Now I obtain a series of "table not found" exceptions but they are thrown for several tables (not only parameters) : is there any hope or should I change of provider ?

Thank you for your time and your patience ^^

Post your complete log file (attch it)

Also what you can try is to install step by steps.
First install V1.0.0
Then V2.0.0
and so on up to lastest.