Update #6100 failed

I get the following error when I try to run updates at the site:

The following updates returned messages

boxes module

Update #6100
Failed: PDOException: SQLSTATE[42S02]: Base table or view not found: 1146 Table '{my_site}.custom_block' doesn't exist: SELECT delta, body, format FROM {custom_block}; Array ( ) in boxes_update_6100() (line 82 of {my_site}/sites/all/modules/boxes/boxes.install).

Looks like we should add a simple check whether such table exists or not.