Is there any limit for Quick Gallery. Each time I try to upload more than (60/70/80...) images I'm getting an error similar to this - (Warning: Invalid argument supplied for foreach() in /wp-content/themes/division/admin/bk_gallery_manager.class.php on line 292). What to do?

Most likely this is server side issue which can be fixed by contacting Your hositng provider.

Please contact Your hosing provider and ask them what limit they have when it comes to sending amount of input fields via POST.

As far as I know they can increase these PHP configuration values:

max_input_vars = 3000

suhosin.post.max_vars = 3000

suhosin.request.max_vars = 3000

each quickgallery thumb uses 13 input fields to handle all settings - so for 100 images You need this values to be at least 1300 - just ask them to increase as much as they can to 2000 - 3000.