Permission denied

Hello Projeqtor staff.

I'm new to Projeqtor and would like to use your software
I use Ubuntu as OS.

and got this error log:

2018-07-30 13:58:23.474 ***** ERROR ***** [] ERROR *****
2018-07-30 13:58:23.474 ***** ERROR ***** [] on file '/var/www/html/portal23/db/maintenance.php' at line (80)
2018-07-30 13:58:23.475 ***** ERROR ***** [] cause = fopen(../files/cron/MIGRATION): failed to open stream: Permission denied
2018-07-30 13:59:28.888 ***** ERROR ***** [] Exception-[42S02] SQLSTATE[42S02]: Base table or view not found: 1146 Table 'projeqtor.resource' doesn't exist
2018-07-30 13:59:28.888 ***** ERROR ***** [] For query : select * from resource where resource.name='admin' and resource.isUser = '1'
2018-07-30 13:59:28.888 ***** ERROR ***** [] Strack trace :
2018-07-30 13:59:28.888 ***** ERROR ***** [] #0 Sql->query called at [/var/www/html/portal23/model/persistence/SqlElement.php:2336]
2018-07-30 13:59:28.888 ***** ERROR ***** [] #1 SqlElement->getSqlElementsFromCriteria called at [/var/www/html/portal23/model/persistence/SqlElement.php:2630]
2018-07-30 13:59:28.888 ***** ERROR ***** [] #2 SqlElement->getSingleSqlElementFromCriteria called at [/var/www/html/portal23/tool/getHash.php:48]
2018-07-30 13:59:28.931 ***** ERROR ***** [] ERROR *****
2018-07-30 13:59:28.931 ***** ERROR ***** [] on file '/var/www/html/portal23/db/maintenance.php' at line (80)
2018-07-30 13:59:28.931 ***** ERROR ***** [] cause = fopen(../files/cron/MIGRATION): failed to open stream: Permission denied
2018-07-30 14:01:31.873 ***** ERROR ***** [] Exception-[42S02] SQLSTATE[42S02]: Base table or view not found: 1146 Table 'projeqtor.resource' doesn't exist
2018-07-30 14:01:31.873 ***** ERROR ***** [] For query : select * from resource where resource.name='admin' and resource.isUser = '1'
2018-07-30 14:01:31.873 ***** ERROR ***** [] Strack trace :
2018-07-30 14:01:31.873 ***** ERROR ***** [] #0 Sql->query called at [/var/www/html/portal23/model/persistence/SqlElement.php:2336]
2018-07-30 14:01:31.873 ***** ERROR ***** [] #1 SqlElement->getSqlElementsFromCriteria called at [/var/www/html/portal23/model/persistence/SqlElement.php:2630]
2018-07-30 14:01:31.873 ***** ERROR ***** [] #2 SqlElement->getSingleSqlElementFromCriteria called at [/var/www/html/portal23/tool/getHash.php:48]
2018-07-30 14:01:31.912 ***** ERROR ***** [] ERROR *****
2018-07-30 14:01:31.912 ***** ERROR ***** [] on file '/var/www/html/portal23/db/maintenance.php' at line (80)
2018-07-30 14:01:31.912 ***** ERROR ***** [] cause = fopen(../files/cron/MIGRATION): failed to open stream: Permission denied

How to fix this?

Kind Regards Dirk