J-BusinessDirectory - I can't register a business on directory using fronted site

I have intalled J-Business Directory without problem but I can't register  a business on directory using fronted site. Besides, the website shows these errors on the offers fronted site:

Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in /home/domains/public_html/libraries/joomla/database/database/mysqli.php on line 263

Warning: Invalid argument supplied for foreach() in /home/domains/public_html/components/com_jbusinessdirectory/views/managecompanyoffers/tmpl/default.php on line 64

Hi,

Can you provide us access to your joomla admin (using contact form)? We will check this.