help!

I bought a mod, and installed as the instruction. However, I got an error message. I sent an email to them but nobody answer. I am trying to fix it by myself, as I thought it may not be a big problem. I need some advice where I should go. The error message is:

Fatal error: Uncaught exception 'ErrorException' with message 'Error: Duplicate column name 'image'<br />Error No: 1060<br />ALTER TABLE `oc_banner_image_description` ADD `image` VARCHAR( 255 ) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL AFTER `title`' in /home/flo10/public_html/system/database/mysqli.php:41 Stack trace: #0 /home/flo10/public_html/vqmod/vqcache/vq2-system_library_db.php(20): DBMySQLi->query('ALTER TABLE `oc...') #1 /home/flo10/public_html/vqmod/vqcache/vq2-admin_controller_design_banner.php(504): DB->query('ALTER TABLE `oc...') #2 /home/flo10/public_html/vqmod/vqcache/vq2-admin_controller_design_banner.php(20): ControllerDesignBanner->checkInstalled() #3 [internal function]: ControllerDesignBanner->index() #4 /home/flo10/public_html/vqmod/vqcache/vq2-system_engine_front.php(42): call_user_func_array(Array, Array) #5 /home/flo10/public_html/vqmod/vqcache/vq2-system_engine_front.php(29): Front->execute(Object(Action)) #6 /home/flo10/public_html/admin/index.php(166): Front->dispa in /home/flo10/public_html/system/database/mysqli.php on line 41.

If is for opencart 1.5.6.4.

Many thanks.

I bought a mod, and installed as the instruction.
is that all, you can tell us about ?