I've done a fresh, clean install of Concrete5, version 5.1.1
Installation went ok, initial configuration went ok, but when I try to access FileManager from dashboard, I get this error:
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An unexpected error occurred.
mysql error: [2013: Lost connection to MySQL server during query] in EXECUTE("select generictype from btFile group by generictype")

Fatal error: Uncaught exception 'ADODB_Exception' with message 'mysql error: [2006: MySQL server has gone away] in EXECUTE("insert into Logs (logType, logText, logIsInternal) values ('exceptions', 'Exception Occurred: mysql error: [2013: Lost connection to MySQL server during query] in EXECUTE(\"select generictype from btFile group by generictype\")\n\n#0 /home/web/concrete/libraries/3rdparty/adodb/adodb.inc.php(918): adodb_throw(\'mysql\', \'EXECUTE\', 2013, \'Lost connection...\', \'select generict...\', false, Object(ADODB_mysql))\n#1 /home/web/concrete/libraries/3rdparty/adodb/adodb.inc.php(893): ADOConnection->_Execute(\'select generict...\', false)\n#2 /home/web/concrete/libraries/3rdparty/adodb/adodb.inc.php(645): ADOConnection->Execute(\'select generict...\', false)\n#3 [internal function]: ADOConnection->Query(\'select generict...\')\n#4 /home/web/concrete/libraries/database.php(62): call_user_func_array(Array, Array)\n#5 [internal function]: Database->__call(\'query\', Array)\n#6 /home/web/concrete/models/search in /home/web/concrete/libraries/3rdparty/adodb/adodb-exceptions.inc.php on line 78
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Note that db user has ALL privileges on database.

Can somebody help me?

Thanks

Dario