You have an error in your SQL syntax; check the manual that corresponds to your

[runnerjp]

where am i going wrong here: 

$insert = mysql_query("REPLACE INTO `users` SET `".$forum."`=`".$timestamp."` where id = `".$id."`")
or die(mysql_error());

[sader]

surround table names, field names db's names by `, but field values surround by ' or "

SELECT * FROM `table` WHERE `name`='user_name';

[Mchl]

That's exactly why you should not use backticks. You use too many of them.

 

$insert = mysql_query("REPLACE INTO users SET $forum ='$timestamp' where id = $id")
or die(mysql_error());