IP Lookup returns no result, only "warning."

[khague]

For the past few weeks when I attempt to look up an IP using this site, I get a note at the top that says
Warning: Cannot modify header information - headers already sent by (output started at /WebDrive/web/v3.whatismyipaddress.com/includes/custom_functions.php:26) in /WebDrive/web/v3.whatismyipaddress.com/public/ip-lookup.php on line 20

And no results.
I'm using Windows 7, latest version of Google Chrome. Are either of those causing the issue? This is my favorite lookup site and it's a drag that I can no longer get results.

[Chrispcritters]

Too many queries in too short a period of time, the error message should indicate that. I'll look into why it's not working correctly. Just wait 15 minutes and you should be fine.

[khague]

No, it now never works for me - not the first time in a day, not the first time in a week.

[khague]

Tried today for the first time in a week... same error message.