Can't download or view published articles through archives

i can’t download or view and i was told to check my error log file which i did and i got this. please kindly tell me what next to do

PHP Version: 5.5.22
Apache Version: N/A
DB Driver: mysql
DB server version: 5.5.44-0ubuntu0.12.04.1-log
ojs2 has produced an error
Message: WARNING: assert(): Assertion failed
In file: /hermes/bosnaweb14a/b2157/ipg.akinbobola/ijmsr/lib/pkp/classes/scheduledTask/Sch
20160328T233154: ijmsr.net/index.php/ijmsr/
ojs2 has produced an error
Message: WARNING: mkdir(): Permission denied
In file: /hermes/bosnaweb14a/b2157/ipg.akinbobola/ijmsr/lib/pkp/classes/file/FileManager.inc.php
At line: 306
Stacktrace:
Server info:
OS: Linux
PHP Version: 5.5.22
Apache Version: N/A
DB Driver: mysql
DB server version: 5.5.44-0ubuntu0.12.04.1-log
ojs2 has produced an error
Message: WARNING: assert(): Assertion failed
In file: /hermes/bosnaweb14a/b2157/ipg.akinbobola/ijmsr/plugins/generic/usageStats/UsageS
20160329T035332: ijmsr.net/index.php/ijmsr/article/view/26/0
ojs2 has produced an error
Message: WARNING: mkdir(): Permission denied
In file: /hermes/bosnaweb14a/b2157/ipg.akinbobola/ijmsr/lib/pkp/classes/file/FileManager.inc.php
At line: 306
Stacktrace:
Server info:
OS: Linux
PHP Version: 5.5.22
Apache Version: N/A
DB Driver: mysql
DB server version: 5.5.44-0ubuntu0.12.04.1-log
ojs2 has produced an error
Message: WARNING: assert(): Assertion failed
In file: /hermes/bosnaweb14a/b2157/ipg.akinbobola/ijmsr/plugins/generic/usageStats/UsageS
20160329T044949: ijmsr.net/index.php/ijmsr/article/view/11
ojs2 has produced an error
Message: WARNING: mkdir(): Permission denied
In file: /hermes/bosnaweb14a/b2157/ipg.akinbobola/ijmsr/lib/pkp/classes/file/FileManager.inc.php
At line: 306
Stacktrace:
Server info:
OS: Linux
PHP Version: 5.5.22
Apache Version: N/A
DB Driver: mysql
DB server version: 5.5.44-0ubuntu0.12.04.1-log
ojs2 has produced an error

The error “mkdir(): Permission denied” indicates a file permissions problem. You webserver needs to be able to write to the files_dir location (as well as cache/ and public/). See:
https://pkp.sfu.ca/wiki/index.php/PKP_Frequently_Asked_Questions#I.27m_having_file_permission_problems.3B_how_should_I_set_file_permissions.3F