Install fail, with open_basedir restriction and Zend uncaught exception errors

My attempt to install Omeka has failed. I get a bunch of errors like this one at the top of the initial 'installation form':

Warning: file_exists() [function.file-exists]: open_basedir restriction in effect. File(/usr/share/php/config.php) is not within the allowed path(s): (/var/www/vhosts/ in /var/www/vhosts/ on line 33

And then after clicking the 'install' button I get some like that again with this 'fatal error' at the bottom of the list:

Fatal error: Uncaught exception 'Zend_Db_Statement_Mysqli_Exception' with message 'Mysqli statement execute error : No data supplied for parameters in prepared statement' in /var/www/vhosts/ Stack trace: #0 /var/www/vhosts/ Zend_Db_Statement_Mysqli->_execute(Array) #1 /var/www/vhosts/ Zend_Db_Statement->execute(Array) #2 /var/www/vhosts/ Zend_Db_Adapter_Abstract->query('? INSERT...', Array) #3 /var/www/vhosts/ Omeka_Db->__call(Array, Array) #4 /var/www/vhosts/ Omeka_Db->query('query', Array) #5 /var/www/vhosts/ Omeka_Db->exec('? IN in /var/www/vhosts/ on line 214

At that point I'm stuck. I'm still waiting to hear back from my server host, but they initially said Omeka should work fine.

I'd appreciate any assistance. Is this something I can fix, is it something my host will have to fix, or what?