How do I update my denon receiver. I can't get Pandora to wok?

On the Denon website they had a similiar complaint about Spotify. They suggested rebooting the receiver by unplugging it and then plugging it back in..
Have you made any changes to your router or modem? They may need a software update.

Is the TV connected to the receiver with a digital connection (coax, or optical)?. Try setting it to PCM on the TV Some receivers don't like it when there is a break between tracks and the signal is lost. You won't get surround (but Pandora is just stereo anyway), but you can still use the Receiver's Dolby or DTS features to go multispeaker. Downside if of course that if you have other Multichannel audio sources through the TV, they may be lost. But it's worth checking..

Have you checked to see if there is a firmware update? You might need to reset back to factory but you will loose any items you put in.

Factory reset by:
1 Turn off the power using ON/STANDBY.
2 Press ON/STANDBY while simultaneously pressing PRESET CHANNEL 2 and PRESET CHANNEL 3.
3 Once the display starts flashing at intervals of about 1 second, release the two buttons

From Denon website!
http://usa.denon.com/us/news/pages/newsdetails.aspx?newstype=news&newsid=89&year=2012

http://us.marantz.com/DocumentMaster/us/PressReleases/PandoraProblem-M.pdf

Check the Denon website. There is a notice for Pandora users. Pandora changed something and Denon products are blocked as of 11/30. They state that they are working on a fix and to check back after 12/6 for the update.

direct from Denons website "

Why can't I access Pandora on my Denon networked product?

Please be advised that Pandora has recently altered certain connection requirements which have temporarily blocked our products from connecting to the Pandora service. Our Engineering Dept. is currently working hard to correct this and will have a firmware update available as soon as possible via the internet to resolve this issue. This should not affect your product's ability to receive other music streaming services. Please visit our website for firmware update schedule information after December 6th.
We sincerely apologize for any inconvenience that Pandora's alteration has caused.

I have the same problem. Used to work even on Iphone 4 and suddenly it just stopped working about 10 days ago. Very strange as i have not updated my iphone (I'm on Version 4.02). My Denon dock is ASD-3W (wifi) connected to Denon 3808CI.
Any info appreciated.