check_query() failure in Drupal 4.6

I installed Instant Messenger 4.5 with Drupal 4.6. and got the following error:
Fatal error: Call to undefined function: check_query() in /www/htdocs/audiens/modules/im/im.module on line 69

I found out that the function check_query() is deprecated and not available in drupal 4.6
So I changed the code on line 69 to db_escape_string() as found in the forum.
Anything else seems to work fine. But I dind't really test it by now.

Use the file at own risk.