Need help with adding new field to forum table

[asandhanam]

Hi,

I'm new to vb and need some help. I added the field 'categoryid' to the forum table. Then i tried to print that categoryid in the header, footer(simply for testing purposes)..i added $foruminfo[categoryid] and also tried $forum[categoryid]. But none of 'em worked. I need to be able to use this categoryid in a plugin with the following code:
i tried the hook location 'global_start'
ob_start();
$categoryid = $foruminfo[categoryid];
include('[domainname]/API/ads.cfm?w=160&h=600&as=2&q=&f=0&categoryid=$catego ryid');
$includedphp = ob_get_contents();
ob_end_clean();

since $foruminfo[categoryid] doesn't print anything, how do i accomplish this.?