Hi, try a "disc cleaner" inserted into unit, its possible the laser reader is dirty - run it a few times then put nav disc back in and try again AND/OR
1/ run the engine and don`t turn off !
2/ insert nav disc
3/ press MENU + ZOOM (down arrow) together and hold for a few seconds till you get "disc error" on diplay
4/ on screen display select SYSTEM LINK
5/ select NEXT (opens CAR STATUS page)
6/ press NEXT (opens YAW RATE page)
7/ press NEXT (opens DIAGNOSIS MENU page)
8/ select UNIT CHECK
9/ select FORCE DOWNLOAD
10/ screen goes blank
11/ message appears - Please Wait. Now downloading software, then "please do not switch off engine"
12/ the progress bar will appear ( Green Bar)
13/ after a while the Honda Main Navigation Screen should re-appear
14/ message appears - The System Provides Route Information .... etc
15/ press OK
16/ on completion your download will operate and map, you may have to drive your car around for a short while, this allows the unit to "pick up" signal.
That`s it - if this does not work, the laser unit (eye) could be faulty ! This worked on my car and occasionally I have to re-run the above (I think condensation can cause this also)
I know it sounds a little long winded but like I said, it worked on my car - I also bought a version 2011 update disc, that is the latest disc that Honda made for my car, your car is the FaceLift Accord, the later version disc 3.xx BUT that disc went faulty after around one month - I think it was a copy - SO I reverted back to my genuine original disc that came with the car which is version 2.1
Hope this helps, let me know how you go on and if I can help further I will.
Was the sat nav working OK before your problem ?