WordPress MU

I was using Register-Plus plug-in in standard Wordpress. It seems to work so far with MU. Has anyone tested this plugin?

I used it to add a custom field to the user's profile, a field called license_id. I was using code in Wordpress to update this field. As far as I can remember, the code below worked in WordPress, but I have had no luck so far in MU. I was in the middle of coding this when I started to install MU so maybe it didn't work. I was hoping someone might know how to accomplish reading a writting to this custom field.

Here is the code that reads it:

global $userdata;
get_currentuserinfo();
$licenseid = get_user_option('license_id',userdata->ID);

But I can not change it. I am trying:

$newvalue = $licenseid;
$option = 'license_id';
update_user_option($userdata->ID,$option,$newvalue,true);

but it doesn't seem to store the new value. Any suggestions.

Thanks.