youre not using mysql_error(), how did you get that error to print? I ask becuase i've seen people do this before:
$query = mysql_query("INSERT INTO. . .");
$result = mysql_query($query);
notice two calls to mysql_query(), the first one is correct, but the 2nd one tries to query a mysql_query(), not a string.
Also, one of those variables may have an unescaped character such as a single or double quote. If you don't have magic quotes set to on, make sure to run addslashes() on your variables.
Anyways, if there is more to your code, please post.
Cgraz