Thanks for the bug report.
Prior to UBB.threads 7.7.3, the following was hard-coded in to all searches.
{$config['TABLE_PREFIX']}USER_GROUPS as t4USER_GROUPS is now only used in the query if you perform a live query with the "Advanced Search Options" and have selected a group.
Your saved search also contains USER_GROUPS in its filter.
This is what's triggering the error. And I am able to reproduce the error.
Give me a day or so to push a fix in to the code, and post a temp fix for it to this thread.
This error only affects version UBB.threads 7.7.3.