MySQL error in file: /engine/modules/show.full.php at line 52

Error Number: 3685

The Error returned was:
Illegal argument to a regular expression.

SQL query:

SELECT * FROM red_post LEFT JOIN red_post_extras ON (red_post.id=red_post_extras.news_id) WHERE category regexp '[[:<:]](1)[[:>:]]' AND alt_name = 'pervyy-respublikanskiy-kanal'