I noticed this problem since earlier this morning. I'm certain I haven't downloaded any new softwares or app. My Norton Antivirus gives me a 'Hack Attempt' when this happens.

The URL I am redirected to is "http://64.111.196.121/rej.php?aid=20165&said=3&keyword=MY SEARCH TERM&d=d2hhbGVtdXRhdGlvbi5jb20&rej=1&b=8"

sledge81, you probably picked up some Malware. That IP address has something to do with whalemutation.com. I see that domain name as being blocked by NoScript, so nothing loads for me. When I allow that domain a crappy website loads after a redirect; hit the Back button, another redirect and a different crappy web site loads. That's a redirect farm.

Install, update, and run these programs in this order. They are listed in order of efficacy.
(Not all programs detect the same Malware, so you may need to run them all to solve your problem.)
These programs are all free for personal use, but some have limited functionality in the "free mode" - but those are features you really don't need to find and remove the problem that you have.
Note: If your Malware infection is bad enough and you are mis-directed to URL's other than what is posted, you may have to use a different PC to download these programs and use a USB stick to transfer them to the afflicted PC.

Malwarebytes' Anti-Malware - http://www.malwarebytes.org/mbam.php
SuperAntispyware - http://www.superantispyware.com/
AdAware - http://www.lavasoftusa.com/software/adaware/
Spybot Search & Destroy - http://www.safer-networking.org/en/index.html
Windows Defender: Home Page - http://www.microsoft.com/windows/prod.../default.mspx
Also, if you have a search engine re-direct problem, see this:
http://deletemalware.blogspot.com/2010/02/remove-google-redirect-virus.html

If these don't find it or can't clear it, post in one of these forums for specialized malware removal help:
http://www.spywarewarrior.com/index.php
http://forum.aumha.org/
http://www.spywareinfoforum.com/
http://bleepingcomputer.com

Whilst the-edmeister replied to sledge81 rather than myself who raised the ticket, I downloaded Malwarebytes' Anti-Malware and running this sorted it out i.e. redirected the first time I select a result no matter the result that was selected.

A very clever malware giving the impression Google and doubleclick were to blame.

Surprised that Google doesn't post an alert on their blog on this one :)

This happened to me too. I noted the beginning of the URL and checked my cookies to see if there were any out there that were similar to the beginning letters of the URL. Sure enough there was one - monstermarketing in my case. Once I deleted the cookie I was no longer misdirected to other web sites.

I had the same problem, real intermittent redirects. Clever little buggers.

I found the solution on another Firefox thread "xul runner 1.9.1 added mysteriously-redirects google-how remove". The link is: xul runner 1.9.1 added mysteriously-redirects google-how remove

If you have tried all the scanning stuff for malware, checked for malicious cookies etc., and still have this problem with redirection of your search results, it can be cured very simply.

In Firefox, go to Tools ->Options->Privacy->beside the box you tick to accept third party cookies (which you can leave ticked), you will see a tab marked->Exceptions. Click on this and in the box type: *googleleads.g.doubleclick.net. Then click the Block button and hit Close. Don't forget the star before the address. No more misdirections via doubleclick!

When the next redirect annoyance comes along - as it surely will, first check that it is not a malware infection of your computer Then have a look at the Cookies for nasties and if necessary clear them. Then just repeat the above process, adding whatever URL initially redirects to the pest advertising site, but don't forget to add the star if you leave off the www., or http:, etc. The star covers all the URL prefixes in use so no need to type them into the box.

It is the redirecting URL that needs blocking as it will be almost impossible to manually block all the advertising site URLs they dish up to you. You will have to be quick to copy the URL before it redirects and the address changes.