Need help with "Call to a member function on a non-object" error

[JJR512]

I'm working on a plugin to forumhome_complete.

When I try to load the forum index, I get this error:

Fatal error: Call to a member function on a non-object in /home/jjr512/public_html/testbbs/index.php(459) : eval()'d code on line 23

Line 23 of the plugin is this:

$DB->query("INSERT INTO test (userid, dateline, text) VALUES (1,1130351299,boo)");

Notes:
I've tried using $DB->query_write as well as $DB->query. No difference. I've tried putting single quotes or double quotes around any and all of the values. No difference. (I'm using hard-coded data for now, as you can see; I'll work on getting variables in there later.)

I've looked at INSERT queries in various stock vB files and all seem to be formatted the same way as this, except for how it's written out over multiple lines. I've tried it that way, too, but it made no difference.

What am I doing wrong?